Table of contents :

• systema skeletale / skeletal system : the bones (pars ossea systematis skeletalis) and cartilages (pars cartilaginea systematis skeletalis) of the body
• systema musculare / muscular system / musculi : in TA terminology, the nomenclature relating to the muscles and to the bursae and synovial sheaths

• cartilage / cartilago (see also diseases of cartilage) : a specialized, fibrous connective tissue, forming most of the temporary skeleton of the embryo, providing a model in which most of the bones develop, and constituting an important part of the growth mechanism of the organism. It exists in several types, the most important of which are hyaline cartilage, elastic cartilage, and fibrocartilage. Also used as a general term to designate a mass of such tissue in a particular site in the body.
• cartilage lacuna : any of the small cavities within the cartilage matrix, containing a chondrocyte, or cartilage cell
• elastic, reticular or yellow cartilage : a substance that is more opaque, flexible, and elastic than hyaline cartilage, and is further distinguished by its yellow color. The interstitial substance is penetrated in all directions by frequently branching fibers which give all the reactions for elastic

Cell types : elastic cartilage chondrocyte
• hyaline cartilage / chondroid : a flexible, somewhat elastic, semitransparent substance with an opalescent bluish tint, composed of a basophilic, fibril-containing interstitial substance with cavities in which the chondrocytes occur. The matrix nearest the chondrocytes is intensely staining; although the matrix appears homogeneous, collagen fibrils may be visualized by polarized light or electron microscopy.

Cell types : hyalinous cartilage chondrocyte
• cellular or parenchymatous cartilage : a variety composed almost entirely of cells, with little interstitial substance
• fibrocartilage / stratified cartilage : a type of cartilage made up of typical cartilage cells (chondrocytes), with parallel thick, compact collagenous bundles forming the interstitial substances, separated by narrow clefts enclosing the encapsulated cells
• circumferential fibrocartilage : fibrocartilage that forms a rim about a joint cavity.
• spongy or connecting fibrocartilage : a disk of fibrocartilage that attaches opposing bones to each other by synchondrosis
• elastic fibrocartilage : fibrocartilage containing elastic fibers.
• stratiform fibrocartilage : cartilage such as that lining the bony grooves lodging certain tendons.
• white fibrocartilage : fibrocartilage in which strong bundles of white fibrous tissue predominate.
• yellow fibrocartilage : fibrocartilage containing bundles of yellow elastic fibers but with little or no white fibrous tissue.
Cell types : fibrocartilage chondrocyte
Localizations :
• fibrocartilago basalis : basal fibrocartilage: the cartilage that fills the foramen lacerum of the skull.
• fibrocartilago basilaris / synchondrosis spheno-occipitalis.
• fibrocartilagines intervertebrales / disci intervertebrales
• fibrocartilago navicularis : a fibrocartilaginous facet on the dorsal surface of the plantar calcaneonavicular ligament that helps form the articular cavity for the head of the talus.
Developmental timing :
• centers of chondrification / protochondral tissue : dense aggregations of embryonic mesenchymal cells at sites of future cartilage formation
• temporary, ossifying or precursory cartilage : any cartilage that is being replaced by bone or that is normally destined to be replaced by bone, as in cartilage bones
• permanent cartilage : cartilage that does not normally become ossified
• calcified cartilage : cartilage in which granules of calcium phosphate and calcium carbonate have been deposited in the interstitial substance
Genetic markers :
• extracellular matrix : collagen type II, collagen type C, aggrecan, link protein
• transcription factors : Sox9, scleraxis
• bone / osseous tissue (see also diseases of bones) : the hard form of connective tissue that constitutes the majority of the skeleton of most vertebrates

Microscopic anatomy :
• organic component
• cell types (osseous or osteoprogenitor cells) of basic multicellular units (BMU) / bone remodeling units (BRU) : relatively undifferentiated cells found on or near all of the free surfaces of bone, which, under certain circumstances, undergo division and transform into ...
• osteoblasts / stromal cells / Gegenbaur's cell produce OPG-L / RANK-L / ODF first (which binds to RANK on osteoclast progenitors) and OPG then (which act as a soluble decoy receptor) => osteocyte
• bone or osseous lacuna : a small cavity within the bone matrix containing an osteocyte and from which slender canaliculi radiate and penetrate the adjacent lamellae to anastomose with the canaliculi of neighboring lacunae, thus forming a system of cavities interconnected by minute canals
• osteoclasts : ITAM-dependent costimulatory signals activated by multiple immunoreceptors are essential for the maintenance of bone homeostasis. OPG-L / RANK-L / ODF and M-CSF are not sufficient to activate the signals required for osteoclastogenesis^ref
• Howship's absorption or resorption lacuna : a pit or concavity found in bones undergoing resorption, frequently containing osteoclasts. Similar lacunae also may be found in eroding surfaces of cementum, in which cementoclasts may or may not be located
• bone matrix / osteoid (35%) : the organic matrix of bone; young bone that has not undergone calcification, consisting of type I collagen / ossein / ostein (90%). Mature type I collagen is cross-linked within the molecule through the a chains and between adjacent collagen molecules by the pyridinium crosslinks, pyridinoline (PYD), and deoxypyridinoline (DPD), providing rigidity and stregth
• osteocollagenous fibers : fibers gathered together into bundles and united by a special binding substance in the interstitial substance of bone
• osteogenetic or osteogenic fibers : precollagenous fibers formed by osteoclasts and becoming the fibrous component of bone matrix.
• osseomucin : the homogeneous ground substance that binds together the collagen and elastic fibrils of bony tissue
• osseomucoid : a mucin existing in bone.
Sympathetic signalling via b₂-AR present on osteoblasts controls bone formation downstream of leptin. The sympathetic nervous system favours bone resorption by increasing expression in osteoblast progenitor cells of the osteoclast differentiation factor RANK-L. This sympathetic function requires phosphorylation (by PKA) of ATF4, a cell-specific CREB-related transcription factor essential for osteoblast differentiation and function. That bone resorption cannot increase in gonadectomized Adrb2-deficient mice highlights the biological importance of this regulation, but also contrasts sharply with the increase in bone resorption characterizing another hypogonadic mouse with low sympathetic tone, the ob/ob mouse. This discrepancy is explained, in part, by the fact that CART, a neuropeptide whose expression is controlled by leptin and nearly abolished in ob/ob mice, inhibits bone resorption by modulating Rankl expression. Leptin-regulated neural pathways control both aspects of bone remodelling, and demonstrates that integrity of sympathetic signalling is necessary for the increase in bone resorption caused by gonadal failure^ref.
• inorganic, or mineral, component (65%) imparts the quality of rigidity to bone : calcium salts
• calcium phosphate (Ca₃(PO₄)₂) (85%)
• calcium carbonate (CaCO₃) (10%)
Types of bone tissues :
• crossed fibers bone / woven bone / nonlamellated bone / primitive bone : bony tissue found in the embryo and young children and in various pathologic conditions in adults, in which the bone fails to show the oriented arrangement of collagen fibers characteristic of lamellated bone

‡ at birth
• concentrical lamellae bone

‡ at puberty
• osteon or lamellar bone : the normal type of adult bone


• compact bone : the compact bone of the shaft of a bone that surrounds the medullary cavity. It is made of haversian systems : osteocytes in concentrically arranged lamellae aroung central haversian canals (blood vessels) and in contact with the blood vessels and with each other through microscopic channels (canaliculi) in the matrix
• cement line : a name applied to a line, visible in microscopic examination of bone in cross section, marking the boundary of an osteon (haversian system).
• bone island : a benign focus of mature cortical bone appearing within trabecular bone on a radiograph
• cancellous, spongy or trabecular bone is named for its appearance. Osteocytes, blood vessels, and matrix are present and parallel arranged, but not arranged in haversian systems. The cavities often contain red bone marrow, which produces RBCs, platelets, and WBCs. It represents only 20-30% of total bone mass but has a turnover rate 10-folds higher than that of compact bone.
• trabeculae of bone : anastomosing bony spicules in cancellous bone which form a meshwork of intercommunicating spaces that are filled with bone marrow.
Bone mass usually increases up to age 30 (in males it is usually 10% higher than in females) and decreases starting since age 40 : in females decline is faster in the 10 years after menopause.
• foramen : natural opening into or through bone.
• foramen nutricium / foramen nutriens / nutrient foramen : any one of the passages that admit the nutrient vessels to the medullary cavity of a bone.
• nutrient vessels : vessels that supply nutritive elements to special tissues, such as arteries entering the substance of bone, or supplying walls of the blood vessels themselves.
• arteria nutricia / nutrient artery / arteria nutriens / medullary artery : any artery that supplies the marrow of a long bone
• capitulum : a little head, or a small eminence on a bone by which it articulates with another bone.
Ontogenesis :
• ossification : the formation of bone or of a bony substance; the conversion of fibrous tissue or of cartilage into bone or a bony substance.
• endochondral or cartilaginous ossification : ossification that occurs in and replaces cartilage => cartilage, endochondral, replacement, or substitution bone : any bone that develops within cartilage, in contrast to membrane bone, ossification taking place within a cartilage model
• intramembranous ossification : ossification that occurs in and replaces connective tissue, as occurs in the calvaria and in periosteal bone formation => membrane bone : any bone that develops within a connective tissue membrane (e.g. skull and facial bones, clavicle, and ribs), in contrast to cartilage bone
• periosteal ossification : a type of intramembranous bone formation
• osteogen : the substance composing the inner layer of the periosteum, from which bone is formed
• metaplastic ossification : the development of bony substance in normally soft structures.
• heterotopic ossification : the formation of bone in abnormal locations, secondary to pathology either at the local site or elsewhere.
• ectopic ossification : a pathological condition in which bone arises in tissues not in the osseous system and in connective tissues usually not manifesting osteogenic properties.
• perichondral ossification : that which occurs in a layered manner beneath the perichondrium or, later, the periosteum.
• centrum or punctum ossificationis / ossification center or point : any point at which the process of ossification begins in bones; in a long bone there is a primary center for the diaphysis and a secondary center for the epiphysis
• centrum or punctum ossificationis primarium / primary ossification center or point : the first point at which a bone begins to ossify
• centrum or punctum ossificationis secundarium / secondary ossification center or point : a point from which ossification proceeds that arises after a primary ossification center; it is concerned with progressive ossification toward the end of a bone
• osteite : an independent bony element or center of ossification
• sesamoid bones : numerous ovoid nodular bones, often small, usually found embedded within a tendon or joint capsule, principally in the hands and feet (ossa sesamoidea manus and ossa sesamoidea pedis, respectively); 2 sesamoid bones, the fabella and patella, are associated with the knee
Classification of bones :
• long bones are the bones of the arms, legs, hands, and feet.
• epiphyses / apophysis ossium : the expanded articular end of a long bone, developed from a secondary ossification center, made of spongy bone covered with a thin layer of compact bone, which during the period of growth is either entirely cartilaginous or is separated from the shaft by the epiphyseal cartilage
• annular epiphyses : secondary growth centers occurring as rings at the periphery of the superior and inferior surfaces of the vertebral body.
• epiphyseal or growth disk or plate / cartilago epiphysialis / conjugation or epiphyseal cartilage : the disk or plate of cartilage interposed between the epiphysis and the shaft of the bone during the period of growth; by its growth the bone increases in length
• metaphysis : the wider part at the extremity of the shaft of a long bone, adjacent to the epiphyseal disk. During development it contains the growth zone and consists of spongy bone; in the adult it is continuous with the epiphysis
• Wagner's line : a thin whitish line at the junction of the epiphysis and diaphysis of a bone, formed by preliminary calcification
• diaphysis / shaft : the elongated cylindrical portion of a long bone, between the epiphyses, which are usually articular and wider than the shaft; it consists of a tube of compact bone, enclosing the marrow canal / medullary cavity contains yellow bone marrow, which is mostly adipose tissue which gradually replaces the red bone marrow during aging
• short bones are the bones of the wrists and ankles.
• flat bones are the bones of the ribs, shoulder blades, hips, and cranium.
• irregular bones are those of the vertebrae and face.
Anatomy : there is a total of 206 bones in the human body.
• endoskeleton / neuroskeleton : the bony and cartilaginous skeleton of the body, exclusive of that part of the skeleton which is of dermal origin

The skeleton is divided into
• axial skeleton (80 bones) protects the brain, spinal cord, sensory organs, and soft tissue of chest cavity and supports the body weight over the legs.
• skull / cranium (28)
• osteocranium : the fetal cranium during its stage of ossification
• neurocranium / brain box (8)
• viscerocranium / splanchnocranium / facial cranium (14):
• maxillary bones (2) forms the floor and medial portion of the rim of the orbit, the walls of the nasal cavity, and the anterior roof of the mouth (hard palate), i.e. the upper jaw
• maxillary sinus (air cavity that opens into nasal cavity);
• palatine process (projection that forms anterior part of hard palate);
• sockets (conical depressions that hold roots of upper teeth).
• zygomatic bones / cheekbone / jugal bone / mala / malar bone / os zygomaticum (2) : the arch of bone beneath the eye that forms the prominence of the cheek. They are found on each side of the skull, articulating with the frontal bone and the maxilla to complete the lateral wall of the orbit. Along the lateral margin, each gives rise to a slender bony extension that curves laterally and posteriorly to meet a process from the temporal bone, together forming the zygomatic arch.
• zygomaticofacial foramen / foramen zygomaticofaciale : the opening on the anterior surface of the zygomatic bone for the zygomaticofacial nerves and vessels.
• zygomatico-orbital foramen / foramen zygomaticoorbitale : of the 2 openings on the orbital surface of each zygomatic bone, which transmit branches of the zygomatic branch of the trigeminal nerve and branches of the lacrimal artery.
• zygomaticotemporal foramen / foramen zygomaticotemporale : the opening on the temporal surface of the zygomatic bone for passage of the zygomaticotemporal nerve.
• Riolan's nosegay : the group of muscles that take their origin from the styloid process of the temporal bone
• palatine bones (2) form the posterior surface of the hard palate. The superior surfaces of the horizontal portion of each contributes to the floor of the nasal cavity. The superior tip of the vertical portion of each forms a small portion of the inferior wall of the orbit.
• foramen palatinum majus / greater palatine foramen / posterior palatine foramen / pterygopalatine foramen / sphenopalatine foramen : the inferior opening of the great palatine canal, found laterally on the horizontal plate of each palatine bone opposite the root of each third molar tooth; it transmits a palatine nerve and artery
• foramina palatina minora / lesser palatine foramina : the openings of the lesser palatine canals behind the palatine crest and the greater palatine foramina.
• mandible (1) forms the lower jaw.
• body (U-shaped portion with lower teeth);
• condyles (oval projections that articulate with the temporal bones);
• sockets (conical depressions that hold roots of lower teeth)
• mental foramen / foramen mentale : an opening on the lateral part of the body of the mandible, opposite the second bicuspid tooth, for passage of the mental nerve and vessels..
• lacrimal bones (2) are located within the orbit on its medial surface and articulate with the frontal, ethmoid, and maxillary bones.
• lacrimal canal (opening for nasolacrimal duct to take tears to nasal cavity).
• nasal bones (2) form the bridge of the nose and articulate with the superior frontal bone and the maxillary bones.
• inferior nasal conchae (2) project from the lateral walls of the nasal cavity.
• vomer (1). The inferior margin articulates with the paired palatine bones and, with the ethmoid bone, supports a prominent partition that forms part of the nasal septum.
• middle ear (auditory ossicles) (6)
• hyphoid bone (1) is U-shaped and hangs below the skull, suspended by ligaments from the styloid processes of the temporal bones, and serves as a base for muscles associated with the tongue and larynx.
• vertebral column
• thoracic cage (25):
• true ribs (14) are 7 pairs that reach the anterior body wall, and are connected to the sternum by separate cartilaginous extensions (costal cartilages).
• false ribs (10) are ribs 8-12 that do not attach directly to the sternum. The last two pairs are floating ribs because they have no connection with the sternum.
• sternum (1) has three parts in the adult. The manubrium articulates with the clavicles of the appendicular skeleton and with the cartilages of the first pair of ribs. The body ends at the xiphoid process.
• appendicular skeleton (126) : provides internal support and positioning of arms and legs; supports and moves axial skeleton.
• pectoral girdle (4)
• scapula (2) is commonly called the "shoulder blade" and is supported and positioned by the skeletal muscles. It has no bony or ligamentous bonds to the thoracic cage, but is extremely important for muscle attachment.
• glenoid fossa (depression that articulates with humerus)
• spine (long, posterior process for muscle attachment)
• acromian process (articulates with clavicle)
• clavicle (2) is commonly called the "collarbone" and articulates with the manubrium of the sternum, and is the only direct connection between the pectoral girdle and the axial skeleton.
• acromial end (articulates with scapula)
• sternal end (articulates with manubrium of sternum)
• upper limbs (60):
• humerus (2) extends from the scapula to the elbow
• head (articulates with the ulna);
• olecranon fossa (posterior, oval depression for the olecranon process of the ulna);
• capitulum humeri / capitulum of humerus / capitellum / little or radial head of humerus : an eminence on the distal end of the lateral epicondyle of the humerus for articulation with the head of the radius
• trochlea (concave surface that articulates with ulna)
• epitrochlea
• radius (2) lies along the lateral side (or thumb side) of the forearm.
• head (articulates with the ulna).
• ulna (2) forms the medial support of the forearm.
• olecranon process (fits into olecranon fossa of humerus);
• semilunar notch (half-moon depression that articulates with the trochlea of ulna).
• carpals (16)
•  proximal row (8) : from thenar to hypothenar
• carpal scaphoid / navicular / os naviculare manus / os scaphoideum (2)
• lunate / semilunar (2)
• triquetrum / pyramidal (2)
• pisiform (2)
• distal row (8) : from thenar to hypothenar
• trapezium (2)
• trapezoid (2)
• capitate (2)
• hamate (2)
• epipyramis / epitriquetrum : a small supernumerary carpal bone sometimes found between the triquetrum, lunate, hamate, and capitate bones
• metacarpals (10) are 5 pairs of bones that articulate with the distal carpal bones forming the palm of the hand.
• pseudoepiphysis : an accessory bone at the distal and the proximal ends of the second metacarpal bone.
• phalanges (28) are 14 pairs of "finger" bones. Four fingers contain three phalanges while the pollex (thumb) has only 2.
• pelvic girdle (2) articulates with the thigh bone.
• os coxae (2) is commonly called the "hip bone," formed from a fusion of three bones (ilium, ischium, and pubis)
• ilium (flared upper portion)
• iliac crest (upper edge of ilium)
• posterior superior iliac spine (posterior continuation of iliac crest)
• ischium (lower, posterior portion)
• pubis (anterior, medial portion)
• pubic symphysis (joint between the two pubic bones)
• pelvis : the inferior portion of the trunk of the body, bounded anteriorly and laterally by the two hip bones and posteriorly by the sacrum and coccyx. The pelvis is divided by a plane passing through the terminal lines into the
• pelvis major or spuria / false, greater or large pelvis : the part of the pelvis superior to a plane passing through the iliopectineal lines.
• pelvis minor / true, lesser or small pelvis : the part of the pelvis inferior to a plane passing through the iliopectineal lines
The superior boundary of the pelvic cavity is the inlet (apertura pelvis superior), and the inferior boundary of the pelvis minor is the outlet (apertura pelvis inferior), which is bounded by the coccyx, the symphysis pubis, and the ischium of either side. The outlet is closed by the coccygeus and levator ani muscles and the perineal fascia, which form the floor of the pelvis. The inlet and outlet each have three important diameters: an anteroposterior (conjugate), an oblique, and a transverse, the relations of which determine types variously classified by different authors
• pelvis ossea / bony pelvis : the ring of bone forming the skeleton of the pelvis, supporting the vertebral column and resting upon the inferior members, and composed of the two hip bones anteriorly and laterally, and the sacrum and coccyx posteriorly.

• Caldwell-Moloy classification :
• gynecoid pelvis (50%) : a pelvis having a rounded oval shape with a well rounded anterior and posterior segment; it represents the normal female pelvis : pelvic brim is a transverse ellipse (nearly a circle); most favorable for delivery
• android pelvis : a pelvis characterized by a wedge-shaped inlet and narrowness of the anterior segment; used as a general designation of a female pelvis showing characters typical of the pelvis in the male. Pelvic brim is triangular; convergent side walls (widest posteriorly); prominent ischial spines; narrow subpubic arch ; more common in white women
• anthropoid pelvis : a female pelvis characterized by a long anteroposterior diameter of the inlet, which equals or exceeds the transverse diameter. Pelvic brim is an anteroposterior ellipse; gynecoid pelvis turned 90°;arrow ischial spines ; much more common in black women
• platypellic or platypelloid pelvis (3%) : a pelvis characterized by flattening of the pelvic inlet, with a short anteroposterior and a wide transverse diameter. Pelvic brim is transverse kidney shape; flattened gynecoid shape
• assimilation pelvis : a pelvis in which the transverse processes of the last lumbar vertebra are fused with the sacrum (high-assimilation pelvis—including 6 vertebral segments), or the last sacral vertebra may fuse with the first coccygeal body (low-assimilation pelvis—including only four vertebral segments).
• beaked pelvis : one with the pelvic bones laterally compressed and their anterior junction pushed forward, as in osteomalacia.
• contracted pelvis : a pelvis in which there is a diminution of 1.5 to 2 cm in any important diameter; when all dimensions are proportionately diminished it is a ...
• generally contracted pelvis / pelvis justo minor : a pelvis that is unusually small, with all its dimensions equally reduced
• infantile or juvenile pelvis : a generally contracted pelvis characterized by an oval shape, a high sacrum, and marked inclination of the walls.
• coxalgic pelvis : one deformed in consequence of hip-joint disease.
• brachypellic pelvis : an oval type of pelvis, the transverse diameter of the inlet exceeding the anteroposterior diameter by 1 to 3 cm.
• dolichopellic pelvis : an elongated pelvis, the anteroposterior diameter of the inlet being greater than the transverse diameter.
• mesatipellic pelvis : a round type of pelvis, the transverse diameter of the inlet being equal to the anteroposterior diameter or being greater by < 1 cm.
• triangular pelvis : one with a triangular inlet.
• round pelvis : one with an inlet of nearly circular outline.
• cordate or cordiform pelvis : one that is somewhat heart shaped.
• dwarf pelvis / pelvis nana : a small pelvis seen in several types of dwarfism.
• flat pelvis / pelvis plana : one in which the anteroposterior dimension is abnormally reduced.
• simple flat pelvis : one with a shortened anteroposterior diameter.
• funnel-shaped pelvis : a female pelvis with a normal inlet, but a greatly narrowed outlet.
• pelvis justo major / giant pelvis : a pelvis that is unusually large, with all its dimensions equally increased.
• rachitic pelvis : one distorted as a result of rickets.
• pelvis spinosa : a rachitic pelvis with the crest of the pubis very sharp.
• osteomalacic pelvis : deformity of the pelvis due to absorption by the bones of their calcium salts, as a result of which the bones become soft and so flexible that they may be stretched or pushed together and cause narrowing of the pelvic inlet.
• pseudo-osteomalacic pelvis : a deformed pelvis simulating one affected with osteomalacia, but resulting from other causes.
• scoliotic pelvis : one deformed as a result of scoliosis.
• kyphotic pelvis : one characterized by increase of the conjugate diameter at the brim, with decrease of the transverse diameter at the outlet, due to close proximity of the ischial spines and tuberosities.
• pelvis obtecta : a kyphotic pelvis in which the vertebral column extends horizontally across the pelvic inlet.
• kyphoscoliotic pelvis : an irregularly contracted pelvis due to rachitic kyphoscoliosis.
• lordotic pelvis : one associated with an anterior curvature in the lumbar region of the vertebral column.
• Otto pelvis : a pelvis in which the acetabulum is depressed, permitting the head of the femur to protrude intrapelvically (see arthrokatadysis)
• spider pelvis : a renal pelvis which in the pyelogram shows the calices as narrow, string-like extensions, resembling the legs of a spider.
• pseudospider pelvis : a congenitally small, long, thin renal pelvis with calices that may simulate renal tumor urographically.
• split pelvis : one with a congenital separation at the symphysis pubis, often associated with exstrophy of the bladder.
• spondylolisthetic pelvis / Prague or Rokitansky's pelvis : one in which the last, or rarely the fourth or third, lumbar vertebra is dislocated in front of the sacrum, more or less occluding the pelvic brim
• pelvic diameter : any diameter of the pelvis.


• pelvic inlet (upper strictus)
• conjugata anatomica pelvis / anatomical conjugate of pelvis / conjugata vera pelvis / anteroposterior or conjugate diameter of pelvis / anatomical, internal, or true conjugate (diameter) / diameter conjugata pelvis : the anteroposterior diameter of the pelvic inlet (superior aperture of the pelvis), measured from the superior margin of the symphysis pubis to the sacrovertebral angle; usually 11 cm
• obstetric conjugate (diameter) / conjugata vera obstetrica : the shortest anteroposterior diameter of the pelvic inlet; the distance from a point 1 cm. below the top of the pubis to the tip of the sacral promontory, measuring 11 to 13 cm. in the normal pelvis (10.5-10.8 cm). So called because it is intimately concerned in the process of labor
• diameter obliqua pelvis / oblique diameter of pelvis : the oblique diameter across the pelvic inlet, measured from one sacroiliac articulation to the iliopubic eminence of the other side. Designated right or left depending on which sacroiliac joint is used for reference; the left is uniformly 0.5 cm. shorter than the right (12 cm vs. 12.5 cm)
• diameter transversa pelvis / transverse diameter of pelvis : the greatest distance from side to side across the pelvic inlet.
• average : 12 cm
• maximal : 13.5 cm
• middle strictus
• transverse diameter of pelvic outlet / biischial diameter : the distance between the medial surfaces of the ischial tuberosities (average length 10.5-11 cm.)
• lower strictus
• conjugata diagonalis pelvis / diagonal conjugate of pelvis / diagonal conjugate diameter : a diameter of the pelvic inlet; the distance from the posterior surface of the symphysis pubis to the tip of the sacral promontory; 12.5-14 cm. Approximate length of fingers introitus to sacrum
• coccygeopubic diameter : the distance from the tip of the coccyx to the under margin of the symphysis pubis; 9-10 cm (12-12.5 cm including coccygeal mobility)
• intertuberal or intertuberous diameter : the distance between the sciatic notches; 11 cm. Approximately width of fist
• conjugata externa pelvis / external conjugate of pelvis / external conjugate diameter / Baudelocque's diameter or line : the distance from the depression under the last lumbar spine to the upper margin of the pubis
• bisiliac diameter : the distance between the 2 most remote points of the iliac crests.
• bicristal diameter : the greatest distance between the external margins of the iliac crests.
• intercristal diameter or distance / distantia intercristalis : the distance between the middle points of the iliac crests
• bispinous diameter : the distance between the opposite spines of the ischia.
• interspinous diameter or distance / distantia interspinosa : the greatest width between the anterior superior iliac spines
• pubotuberous diameter : the distance from the tuberosity of the ischium to a point on the superior ramus of the pubis which is located directly perpendicular to the tuberosity.
• sacropubic diameter : the distance from the tip of the sacrum or coccyx to the lower margin of the symphysis pubis.
• lower limbs (60):
• femur (2), commonly called the "thigh bone," is the longest, strongest, and heaviest bone in the body. Distally, it articulates with the tibia at the knee joint. The head (epiphysis) articulates with the pelvis at the acetabulum.
• head (round process that articulates with hip bone);
• neck (constricted portion distal to head);
• greater trochanter (large lateral process for muscle attachment);
• lesser trochanter (medial process for muscle attachment);
• condyles (rounded processes that articulate with tibia).
• tibia (2), commonly called the "shinbone," is the large medial bone of the leg, attached to the patella by a ligament
• condyles (articulates with femur);
• medial malleolus (distal process - the medial "ankle bone").
• fibula (2) parallels the lateral border of the tibia.
• head (articulates with tibia);
• lateral malleolus (distal process -- the lateral "ankle bone").
• patella (2) is the "knee cap."
• Blackburne-Peel ratio : the ratio of the perpendicular distance between the tibial and patellar articular surfaces to the length of the patellar articular surface with the knee in 30° of flexion; it is equal to 0.8 in the normal knee
• Insall-Salvati ratio : the ratio of the length of the ligamentum patellae to the height of the patella, equal to approximately 1 in the normal knee
• tarsals (14) include 7 pairs of bones :
• calcaneus (heel bone)
• talus / astragalus (articulates with calcaneus, tibia and fibula)
• cuboid
• tarsal scaphoid / navicular bone / os naviculare (pedis) : the ovoid-shaped tarsal bone that is situated between the talus and the three cuneiform bones
• 1^st cuneiform
• 2^nd cuneiform
• 3^rd cuneiform
• metatarsals (10) support the sole of the foot and numbered I to V from medial to lateral with the distal ends forming the ball of the foot.
• phalanges (28) have the same arrangement as with the fingers and thumb only with the toes and great toe (hallux).
Genetic markers :
• extracellular matrix : collagen type I, osteocalcin, bone sialoprotein, alkaline phosphatase
• transcription factors : Cbfa1, osterix
Web resources :
• All bones organized by region at the University of Arkansas for Medical Sciences (UAMS) Department of Anatomy
• Interactive Knee Program
• joints (see also diseases of joints)
• capsula articularis / articular capsule / joint capsule / synovial capsule : the sac-like envelope which encloses the cavity of a synovial joint by attaching to the circumference of the articular end of each involved bone; it consists of a fibrous membrane and a synovial membrane
• articular cartilage / cartilago articularis / arthrodial cartilage / diarthrodial cartilage / investing cartilage / obducent cartilage : a thin layer of cartilage, usually hyaline, on the articular surface of bones in synovial joints
• connecting cartilage / interosseous cartilage : cartilage connecting the surfaces of an immovable joint
• synovium / membrana synovialis capsulae articularis / stratum synoviale capsulae articularis : synovial membrane of articular capsule: the inner of the 2 layers of the articular capsule of a synovial joint, composed of loose connective tissue and having a free smooth surface that lines the joint cavity. It secretes the synovial fluid
• villi synoviales / synovial villi : slender projections of the synovial membrane from its free inner surface into the joint cavity.
• synovia / synovial fluid : a transparent alkaline viscid fluid, resembling the white of an egg, secreted by the synovial membrane, and contained in joint cavities, bursae, and tendon sheaths
• look : clean
• consistence : viscous
• quantity : 0-1 mL/joint
• glucose : > (glycemia - 20 mg/dL)
• proteins : 1.3 g / dL (20% of the normal protidemia
• WBCs < 2,000 / mL
• PMN < 25%
Web resources : Synovial fluid at Weizmann Institute
Cell types :
• synovial cell A
• synovial cell B / synovial cells : fibroblasts lying between the cartilaginous fibers in the synovial membrane of joints.
• ligament : a band of tissue that connects bones. Some ligaments are distinct fibrous structures; some are folds of fascia
• articular disk / discus articularis : a pad composed of fibrocartilage or dense fibrous tissue found in some synovial joints (acromioclavicular (Weitbrecht's cartilage), temporomandibular, distal radioulnar, and sternoclavicular joints and between the symphysial surfaces of the pubic bones); it extends into the joint from a marginal attachment at the articular capsule and in some cases completely divides the joint cavity into two separate compartments.
• articular meniscus / joint meniscus / meniscus articularis : a pad, commonly a wedge-shaped crescent of fibrocartilage or dense fibrous tissue, found in some synovial joints; one side forms a marginal attachment at the articular capsule and the other 2 sides extend into the joint, ending in a free edge.
• parameniscus : the structure or area around the menisci (semilunar fibrocartilages) of the knee
They are classified according to their permitted range of motion:
• synarthrosis : a bony junction that is immovable and is connected by solid connective tissue; the two types are the fibrous joint (junctura fibrosa) and the cartilaginous joint (junctura cartilaginea); found between cranial bones and facial bones.
• amphiarthrosis (slightly movable); symphysis; disc of fibrous cartilage between bones; between vertebrae and pubic bones
• articulatio bicondylaris / bicondylar articulation or joint : a condylar joint with a meniscus between the articular surfaces, as in the temporomandibular joint
• junctura synovialis / synovial joint / diarthrosis / diarthrodial joint or articulatio / synovial articulations : a specialized joint permitting more or less free movement, the union of the bony elements being surrounded by an articular capsule enclosing a cavity lined by synovial membrane
• unilocular joint : a synovial joint having only one cavity
• articulatio complexa / articulatio composita / composite joint : a type of synovial joint in which more than two bones are involved; called also compound articulation or joint.
• articulatio plana / plane articulation / arthrodia / gliding articulation / plane or gliding joint / arthrodial joint : a type of synovial joint in which the opposed surfaces are flat or only slightly curved. Although movement is possible, ligaments usually restrict such movement. Gliding joints are found at the ends of the clavicles, between the carpal and tarsal bones, and between the articular facets of adjacent vertebrae.
• articulatio sellaris / sellar or saddle joint / articulatio condylaris inversa / articulatio ovoidalis / ovoid articulation / saddle articulation : a type of synovial joint in which the articular surface of one bone is concave in one direction and convex in the direction at right angles to the first (concavoconvex), and the articular surface of the second bone is reciprocally convexoconcave; movement is possible along two main axes at right angles to each other. Saddle joints are found at the base of the thumb (carpometacarpal joint). "Twiddling the thumbs" is the best example of movement of the saddle joints.
• articulatio simplex / simple joint : a type of synovial joint in which only two bones are involved
• enarthrosis / articulatio spheroidea / spheroidal joint / ball-and-socket articulation or joint / spheroidal articulation / multiaxial or polyaxial joint /  enarthrodial joint : a type of synovial joint in which a spheroidal surface on one bone (“ball”) moves within a concavity (“socket”) on the other bone; it is the most movable type of joint. They occur at the shoulder and hip
• articulatio cotylica : a type of ball and socket joint
• hinge joints permit angular movement in a single plane, as with the opening and closing of a door. Hinge joints are found between the occipital bone and atlas in the axial skeleton, and the elbow, knee, ankle, and interphalangeal joints of the appendicular skeleton.
• pivot joints allow only for rotation as found between the atlas and axis enabling the rotation of the head. They are also found between the head of the radius and the proximal shaft of the ulna, permitting pronation and supination of the palm.
• ellipsoidal joints allow angular motion in two planes -- along or across the length of an oval. In an ellipsoidal joint, an oval articular face is nestled within a depression of an opposing surface. Such joints connect fingers (metacarpal bones) and toes (metatarsal bones).
• intervertebral disks / disci intervertebrales / fibrocartilagines intervertebrales / intervertebral cartilages / fibrocartilage / ligaments : the 23 plates of fibrocartilage found, from the axis to the sacrum, between the lower and upper sides (cartilagineous plate and epiphysary ring) of the bodies of adjacent vertebrae, each consisting of a fibrous ring (anulus fibrosus / outer part) enclosing a pulpy center (nucleus pulposus / inner part). The hydration of the nucleus pulposus decreases during daytime (decreasing overall body height by 2 cm) and with aging

Cell types : interverterbral disk pulpy nucleus cell
• muscles
• sliding filament theory : a theory which postulates that the thin and thick filaments of a myofibril slide past each other, while maintaining their length, during muscle contraction
• skeletal muscle / musculi skeleti (see also diseases of skeletal muscles and sports medicine) : striated muscles that are attached to bones and typically cross at least one joint

Organogenesis : myoglia / border fibril : a fibrillar substance formed by muscle cells, and present only during early embryogenesis of muscle fibers
3 determination factors of the basic helix–loop–helix myogenic regulatory factor (MRF) family, Myf3 / Myod, Myf5 and Myf6 / herculin / Mrf4, are thought to direct this transition because double- or triple-mutant mice totally lack skeletal muscle fibres and myoblasts. In the absence of these factors, progenitor cells remain multipotent and can change their fate. Gene targeting studies have revealed hierarchical relationships between these and the other MRF gene Myf4 / myogenin, where the latter is regarded as a differentiation gene^ref. In the embryo and in the adult, skeletal muscle growth is dependent on the proliferation and the differentiation of muscle progenitors present within muscle masses. Despite the importance of these progenitors, their embryonic origin is unclear. Electroporation of GFP in chick somites, video confocal microscopy analysis of cell movements, and quail-chick grafting experiments to show that the dorsal compartment of the somite, the dermomyotome, is the origin of a population of muscle progenitors that contribute to the growth of trunk muscles during embryonic and fetal life. Furthermore, long-term lineage analyses indicate that satellite cells, which are known progenitors of adult skeletal muscles, derive from the same dermomyotome cell population. Embryonic muscle progenitors and satellite cells share a common origin that can be traced back to the dermomyotome^ref. During vertebrate development, successive phases of embryonic and fetal myogenesis lead to the formation and growth of skeletal muscles. Although the origin and molecular regulation of the earliest embryonic muscle cells is well understood, less is known about later stages of myogenesis. A new cell population expresses the transcription factors Pax3 and Pax7 but no skeletal-muscle-specific markers. These cells are maintained as a proliferating population in embryonic and fetal muscles of the trunk and limbs throughout development. Using a stable green fluorescent protein (GFP) reporter targeted to Pax3, they constitute resident muscle progenitor cells that subsequently become myogenic and form skeletal muscle. Late in fetal development, these cells adopt a satellite cell position characteristic of progenitor cells in postnatal muscle. In the absence of both Pax3 and Pax7, further muscle development is arrested and only the early embryonic muscle of the myotome forms. Cells failing to express Pax3 or Pax7 die or assume a non-myogenic fate. This resident Pax3/Pax7-dependent progenitor cell population constitutes a source of myogenic cells of prime importance for skeletal muscle formation, a finding also of potential value in the context of cell therapy for muscle disease^ref.
Histology :
• voluntary muscle : any muscle that normally is under the control of the will; such muscles are nearly always composed of striated fibers.
• neuromuscular junction (NMJ)
• Leydig's cylinders : bundles of muscular fibers separated by partitions of protoplasm
• secondary synaptic or subneural clefts : evenly spaced lamella-like clefts within the primary synaptic cleft, formed by infoldings of the sarcolemma into the underlying sarcolemma of muscle
• muscle bundle : one of the primary longitudinal subdivisions of a muscle, made up of muscle fibers and separated from other bundles by fascial septa or perimysium.
• sarcolemma = cell membrane
• sarcoplasm = cytoplasm
• subsarcolemmal cisternae : hollow swellings of the tubules of the sarcoplasmic reticulum; they participate in the coupling of the sarcoplasmic reticulum with the sarcolemma in cardiac muscle.
• attachment plaques : small regions of increased density along the sarcolemma of skeletal muscles to which myofilaments seem to attach
• dense body : any of the small regions of increased density in the sarcoplasm of skeletal muscles to which myofilaments seem to attach
• bands :a n elongated area with parallel or roughly parallel borders that is distinct from the surrounding surface by its color, texture, or other characteristics


• A band or disk / Q, anisotropic or transverse disk : the dark-staining zone of a sarcomere, whose center is traversed by the paler H band, which in turn contains the darker M band
• contraction band : one of the bands seen by light microscopy in fully contracted muscle on either side of the Z band, caused by distortion of the ends of the myosin filaments by the Z band
• H band / Hensen's or Engelmann's disk : a relatively pale zone sometimes seen traversing the center of the A band of fibrils of striated muscle
• I band / isotropic or J disk : the band or disk within a striated muscle fibril that appears as a light region under the light microscope and as a dark region under polarized light; it contains the proteins actin, troponin, and tropomyosin
• M band or disk / Hensen's line / mesophragma :  the narrow dark band in the center of the H band of the sarcomere
• Z band, disk or line / Amici's disk / Dobie's line or layer / intermediate disk / Krause's membrane / telophragma / thin disk : a thin membrane seen on longitudinal section as a dark line in the center of the I band; the distance between successive Z bands serves to delimit the sarcomeres of striated muscle
• Brücke's lines : broad bands alternating with Z bands in the fibrils of the striated muscles.
• inophragma : ground membrane; a name given to the Z band and M band (q.v. under band ) because they continue uninterruptedly as transverse membranes through all the adjoining fibrils of a muscle fiber
• triad (T) system : a system of transverse tubular invaginations (T, or transverse, tubules) of the sarcolemma, each of which penetrates deep into the muscle fiber. In mammalian skeletal muscle, they are located at the junction of the A band with the I band, and in mammalian cardiac muscle at the level of the Z band; the system plays a role in the excitation and relaxation of muscle and provides an important additional surface for the exchange of metabolites between muscle and the extracellular space
• triad of skeletal muscle : a pair of terminal cisterns in close apposition to the T tubule, running transversely across a myofibril of skeletal muscle; in mammalian muscle there are two triads to each sarcomere, situated at the A band–I band junction
• terminal cisterns : pairs of transversely oriented channels that are confluent with the sarcotubules, which together with an intermediate T tubule constitute a triad of skeletal muscle
• transverse (T) tubule : the transverse intracellular tubules invaginating from the cell membrane and surrounding the myofibrils of the T system of skeletal and cardiac muscle, serving as a pathway for the spread of electrical excitation within a muscle cell, enabling the nearly simultaneous activation of all myofibrils; in skeletal muscle, a T tubule is the intermediate element of a triad of tubular structures, the other elements being a pair of terminal cisterns
• dumbbells of Schäfer :  microscopic bodies found in striated muscular tissue
Cell types : muscle fiber : any of the cells of skeletal or cardiac muscle tissue. Skeletal muscle fibers are cylindrical multinucleate cells containing contracting myofibrils, across which run transverse striations, enclosed in a sarcolemma. Cardiac muscle fibers contain one or sometimes two nuclei and myofibrils and are separated from one another by an intercalated disk; although striated, cardiac muscle fibers branch to form an interlacing network.
• extrafusal fibers : ordinary muscle fibers, as opposed to the intrafusal fibers of the muscle spindle.
• type I fibres / red muscle fibres / slow twitch muscle fibers : small dark muscle fibers rich in mitochondria, myoglobin, and sarcoplasm and with only faint cross-striping; designed for slow but repetitive contractions over long periods of time (slow oxidation and contraction, high effort resistance and aerobic capacity)
• type IIa fibres / intermediate muscle fibres : muscle fibers having characteristics intermediate between red and white muscle fibers.
• type IIb fibres / white muscle fibres / fast twitch muscle fibers : paler-colored muscle fibers of larger diameter than slow twitch fibers, and having less sarcoplasm and more prominent cross-striping; used for forceful and rapid contractions over short periods of time (very fast contraction, very low effort resistance, large motor units in neocortex, regulates subtle movements). The peculiar protein is a-actinin-3 (ACTN3)
• dark fibers : muscle fibers rich in sarcoplasm and having a dark appearance.
• light fibers : muscle fibers poor in sarcoplasm and therefore more transparent than dark fibers.
• skeletal muscle stem cells
• neuromuscular spindle and myotatic reflex
Motor unit potential : the sum of all synchronous depolarization potentials generated by excitation of all muscular fibers within a given motor unit
Muscle contractions :  a shortening or reduction in size; in connection with muscles contraction implies shortening and/or development of tension
• concentric or shortening contraction : a muscle contraction in which the ends of the muscle move closer together, as when a flexed limb is extended
• eccentric or lengthening contraction : a muscle contraction in which the ends of the muscle move farther apart, as when a limb is forcibly flexed
• isometric contraction (d = k) : muscle contraction without appreciable shortening or change in distance between its origin and insertion
• isotonic contraction (F = k) : muscle contraction without appreciable change in the force of contraction; the distance between the muscle's origin and insertion becomes less.
• isokinetic contraction (same force in all directions)
• twitch : a brief contractile response of a skeletal muscle elicited by a single maximal volley of impulses in the motor neurons supplying it
• Rieger's brake phenomenon : the tendency of a muscle to maintain itself in its normal resting position
• Weber's paradox : the elongation of a muscle which has been so stretched that it cannot contract.
• idiodynamic control : nerve impulses from the cells of the ventral gray column and the motor nuclei of the brain that maintain the muscles in their normal trophic condition.
During intense contractions creatine phosphate and glucose are used, while during moderate contractions glycogen and FFAs are catabolyzed.
Skeletal muscle is critically important to human performance and health, but little is known of the genetic factors influencing muscle size, strength, and its response to exercise training. The Functional single nucleotide polymorphisms (SNP) Associated with Muscle Size and Strength, or FAMuSS, Study is a multicenter, NIH-funded program to examine the influence of gene polymorphisms on skeletal muscle size and strength before and after resistance exercise training. 100 men and women, age 18 - 40 yr, will train their nondominant arm for 12 wk. Skeletal muscle size (magnetic resonance imaging) and isometric and dynamic strength will be measured before and after training. Individuals whose baseline values or response to training deviate > or = 1.5 SD will be defined as outliers and examined for genetic variants. Initially candidate genes previously associated with muscle performance will be examined, but the study will ultimately attempt to identify genes associated with muscle performance. FAMuSS should help identify genetic factors associated with muscle performance and the response to exercise training. Such insight should contribute to our ability to predict the individual response to exercise training but may also contribute to understanding better muscle physiology, to identifying individuals who are susceptible to muscle loss with environmental challenge, and to developing pharmacologic agents capable of preserving muscle size and function^ref. Myostatin / growth differentiation factor 8 (GDF8) mutation associated with gross muscle hypertrophy in a child^ref.
Anatomy / muscle groups :
• musculus dilatator / dilator (muscle) : a general term for a muscle that dilates
• musculus articularis / articular muscle : a muscle that is attached at one end to the synovial capsule of a joint.
• musculus cutaneus / cutaneous muscle : striated muscle that inserts into the skin, such as the platysma.
• musculus fusiformis / fusiform muscle : a spindle-shaped muscle in which the fibers are approximately parallel to the long axis of the muscle but converge upon a tendon at either end.
• musculus triangularis / triangular muscle : a muscle that is triangular in shape.
• musculus quadratus / quadrate muscle : a square-shaped muscle.
• musculus orbicularis / orbicular muscle : a muscle that encircles a body opening, such as the eye or mouth.
• fixation or fixator muscles : accessory muscles that serve to steady a part.
• musculus semipennatus or unipennatus / semipennate or unipennate muscle : a muscle in which the fiber bundles approach the tendon of insertion from only one direction and are inserted through only a small segment of its circumference
• musculus bipennatus or pennatus / bipennate, penniform or pennate muscle : a muscle in which the fibers approach the tendon of insertion from a wide area and are inserted through a large segment of its circumference
• musculus multipennatus / multipennate muscle : a muscle in which the fiber bundles converge to several tendons.
• musculus sphincter / sphincter muscle : a ringlike muscle that closes a natural orifice; called also sphincter.
• congenerous muscles : muscles having a common action or function
• agonistic muscle : a muscle opposed in action by another muscle, called the antagonist
• synergic or synergistic muscles : muscles that assist one another in action.
• antagonistic muscle : a muscle that counteracts the action of another muscle, called the agonist
• antigravity muscles : those muscles, mainly extensors of the knees, hips, and back, that by their tone resist the constant pull of gravity in the maintenance of normal posture.
• appendicular muscles : the muscles of a limb
• cruciate muscle / musculus cruciatus : a muscle in which the fiber bundles are arranged in the shape of an X
• emergency muscles : muscles which ordinarily are not required in the performance of an act but which assist the prime movers when an act is performed with great force
• epimeric muscle : a muscle derived from an epimere and innervated by a posterior ramus of a spinal nerve
• hypomeric muscle : a muscle derived from a hypomere and innervated by an anterior ramus of a spinal nerve.
• intrinsic muscle : a muscle that is contained (origin, belly, and insertion) in the same limb or part.
• extrinsic muscle : a muscle that does not originate in the same limb or part in which it is inserted.
• striated or striped muscle : any muscle whose fibers are divided by transverse bands into striations, including cardiac and voluntary muscle; often used as a synonym for voluntary muscle
• postaxial muscle : a muscle on the dorsal side of a limb.
• preaxial muscle : a muscle on the ventral side of a limb
• fast or white muscle : the paler-colored muscle tissue of some mammals, composed of fast twitch muscle fibers
• slow or red muscle : the darker-colored muscle tissue of some mammals, composed of slow twitch muscle fibers
• vestigial muscle : a muscle that was once well developed but through evolution has become rudimentary.
• yoked muscles : muscles that normally act simultaneously and equally, as in moving the eyes
• musculi capitis : the muscles of the head.
• facial and masticatory muscles / musculi faciales et masticatores
• musculi faciales / musculi faciei / facial muscles / muscles of (facial) expression : a group of cutaneous muscles of the facial structures, which includes the muscles of the scalp, ear, eyelids, nose, and mouth, and the platysma
• musculus depressor anguli oris / depressor muscle of angle of mouth : origin, lower border of mandible; insertion, angle of mouth; innervation, facial; action, pulls down angle of mouth.
• musculus depressor labii inferioris / depressor muscle of lower lip / musculus quadratus labii inferioris : origin, anterior portion of lower border of mandible; insertion, orbicularis oris and skin of lower lip; innervation, facial; action, depresses lower lip.
• musculus depressor septi nasi / depressor muscle of nasal septum : origin, incisor fossa of maxilla; insertion, ala and septum of nose; innervation, facial; action, contracts nostril and depresses ala.
• musculus depressor supercilii / superciliary depressor muscle : a name given a few fibers of the orbital part of the orbicularis oculi muscle that are inserted in the eyebrow, which they depress.
• musculi incisivi labii inferioris / incisive muscles of inferior lip : small bundles of muscle fibers, one arising from the incisive fossa of the mandible on each side and passing laterally to the angle of the mouth.
• musculi incisivi labii superioris / incisive muscles of superior lip : small bundles of muscle fibers, one arising from the incisive fossa of the maxilla on each side and passing laterally to the angle of the mouth.
• musculus incisurae terminalis [Santorini] / musculus incisurae helicis : an inconstant muscular slip continuing forward from the m. tragicus to bridge the incisure of the cartilaginous meatus.
• musculi auriculares / auricular muscles : the intrinsic auricular muscles that extend from one part of the auricle to another, including
• musculus antitragicus / antitragicus muscle : origin, outer part of antitragus; insertion, caudate process of helix and anthelix; innervation, temporal and posterior auricular.
• musculus auricularis anterior / anterior auricular muscle : origin, superficial temporal fascia; insertion, cartilage of ear; innervation, facial; action, draws the auricle forward.
• musculus auricularis posterior / posterior auricular muscle : origin, mastoid process; insertion, cartilage of ear; innervation, facial; action, draws auricle backward.
• musculus auricularis superior / superior auricular muscle : origin, galea aponeurotica; insertion, cartilage of ear; innervation, facial; action, raises auricle.
• musculus tragicus / muscle of tragus : a short, flattened vertical band on the lateral surface of the tragus, innervated by the auriculotemporal and posterior auricular nerves.
• musculus transversus auriculae or auricularis / transverse muscle of auricle : origin, cranial surface of auricle; insertion, circumference of auricle; innervation, posterior auricular; action, retracts helix.
• musculus obliquus auriculae / musculus obliquus auricularis / oblique muscle of auricle : origin, cranial surface of concha; insertion, cranial surface of auricle above concha; innervation, temporal and posterior auricular (branches of facial).
• musculus helicis major / helicis major muscle : origin, spine of helix; insertion, anterior border of helix; innervation, auriculotemporal and posterior auricular (branches of facial); action, tenses skin of auditory canal.
• musculus helicis minor / helicis minor muscle : origin, anterior rim of helix; insertion, concha; innervation, temporal, posterior auricular.
• musculus buccinator / buccinator muscle : origin, buccinator ridge of mandible, alveolar process of maxilla, pterygomandibular ligament; insertion, orbicularis oris at angle of mouth; innervation, buccal branch of facial; action, compresses cheek and retracts angle of the mouth.
• musculus corrugator supercilii / Koyter's muscle : origin, medial end of superciliary arch; insertion, skin of eyebrow; innervation, facial; action, draws eyebrow downward and medially
• musculus epicranius / epicranial muscle : a name given the muscular covering of the scalp, including
• musculus occipitofrontalis / occipitofrontal muscle : origin, VENTER FRONTALIS—galea aponeurotica, VENTER OCCIPITALIS (musculus occipitalis)— highest nuchal line of occipital bone; insertion, VENTER FRONTALIS (musculus frontalis)—skin of eyebrows and root of nose, VENTER OCCIPITALIS—galea aponeurotica; innervation, VENTER FRONTALIS—temporal branch of facial, VENTER OCCIPITALIS—posterior auricular branch of facial; action, VENTER FRONTALIS—raises eyebrows, VENTER OCCIPITALIS—draws scalp posteriorly.
• musculus temporoparietalis / temporoparietal muscle : origin, temporal fascia above ear; insertion, galea aponeurotica; innervation, temporal branches of facial; action, tightens scalp.
• galea aponeurotica
• musculus levator anguli oris / levator muscle of angle of mouth / musculus caninus : origin, canine fossa of maxilla; insertion, orbicularis oris and skin at angle of mouth; innervation, facial; action, raises angle of mouth.
• musculus levator labii superioris / levator muscle of upper lip / musculus quadratus labii superioris : origin, lower orbital margin; insertion, muscle of upper lip; innervation, facial nerve; action, raises upper lip.
• musculus levator labii superioris alaeque nasi / levator muscle of upper lip and ala of nose : origin, nasal process of maxilla; insertion, cartilage and skin of ala nasi, and upper lip; innervation, infraorbital branch of facial; action, raises upper lip and dilates nostril.
• musculus levator palpebrae superioris / levator muscle of upper eyelid : origin, upper border of optic foramen; insertion, tarsal plate and skin of upper eyelid; innervation, oculomotor; action, raises upper lid.
• musculus mentalis : origin, incisive fossa of mandible; insertion, skin of chin; innervation, facial; action, wrinkles skin of chin.
• musculus nasalis / nasal muscle : origin, maxilla; insertion, PARS ALARIS—ala of nose, PARS TRANSVERSA—by aponeurotic expansion with fellow of opposite side; innervation, facial; action, PARS ALARIS (musculus dilator naris)—aids in widening nostril, PARS TRANSVERSA (musculus compressor naris)—depresses cartilage of nose.
• musculus orbicularis oris / orbicular muscle of mouth, comprising a pars labialis, fibers restricted to the lips, and a pars marginalis, fibers blending with those of adjacent muscles; innervation, facial; action, closes and protrudes lips.
• musculus risorius / risorius muscle : origin, fascia over masseter; insertion, skin at angle of mouth; innervation, buccal branch of facial; action, draws angle of mouth laterally.
• musculus tarsalis superior / superior tarsal muscle : origin, m. levator palpebrae superioris; insertion, tarsal plate of upper eyelid; innervation, sympathetic; action, widens palpebral fissure.
• musculus tarsalis inferior / inferior tarsal muscle : origin, inferior rectus muscle; insertion, tarsal plate of lower eyelid; innervation, sympathetic; action, widens palpebral fissure.
• musculus transversus menti / transverse muscle of chin : superficial fibers of the depressor anguli oris which turn back and cross to the opposite side.
• musculus procerus / procerus muscle : origin, fascia over nasal bone; insertion, skin of forehead; innervation, facial; action, draws medial angle of eyebrows down.
• musculus zygomaticus (major) / greater zygomatic muscle : origin, zygomatic bone in front of temporal process; insertion, angle of mouth; innervation, facial; action, draws angle of mouth backward and upward.
• musculus zygomaticus minor / lesser zygomatic muscle : origin, zygomatic bone near maxillary suture; insertion, orbicularis oris and levator labii superioris; innervation, facial; action, draws upper lip upward and laterally
• musculus orbicularis oculi / orbicular muscle of eye : the oval sphincter muscle surrounding the eyelids, consisting of 3 parts: origin, PARS ORBITALIS—medial margin of orbit, including frontal process of maxilla, PARS PALPEBRALIS—medial canthus, medial palpebral ligament, PARS LACRIMALIS—posterior lacrimal crest; insertion, PARS ORBITALIS—near origin after encircling orbit, PARS PALPEBRALIS—fibers intertwine to form lateral palpebral raphe, PARS LACRIMALIS—lateral palpebral raphe, upper and lower tarsi; innervation, facial; action, closes eyelids, wrinkles forehead, compresses lacrimal sac.
• musculi masticatorii / masticatory muscles / muscles of mastication : a group of muscles responsible for the movement of the jaws during mastication, including the masseter, temporal, and medial and lateral pterygoid muscles
• musculus temporalis / temporal muscle : origin, temporal fossa and fascia; insertion, coronoid process of mandible; innervation, mandibular; action, closes jaws.
• musculus masseter / masseter muscle : origin, PARS SUPERFICIALIS—zygomatic process of maxilla and inferior border of zygomatic arch, PARS PROFUNDA—inferior border and medial surface of zygomatic arch; insertion, PARS SUPERFICIALIS—angle and ramus of mandible, PARS PROFUNDA—superior half of ramus and lateral surface of coronoid process of mandible; innervation, mandibular division of trigeminal; action, raises mandible, closes jaws.
• musculus pterygoideus lateralis / lateral pterygoid muscle (2 heads): origin, SUPERIOR HEAD—lateral surface of greater wing of sphenoid and infratemporal crest; INFERIOR HEAD—lateral surface of lateral pterygoid plate; insertion, neck of condyle of mandible, temporomandibular joint capsule; innervation, mandibular division of trigeminal; action, protrudes mandible, opens jaws, moves mandible from side to side.
• musculus pterygoideus medialis / medial pterygoid muscle : origin, lateral pterygoid plate, tuberosity of maxilla; insertion, medial surface of ramus and angle of mandible; innervation, mandibular division of trigeminal; action, closes jaws.
• ocular muscles
• intraocular muscles : the intrinsic muscles of the eyeball.
• iridic muscles : the muscles controlling the iris
• musculus ciliaris / ciliary muscle : origin, scleral spur; insertion, outer layers of choroid and ciliary processes; innervation, oculomotor, parasympathetic; action, affects shape of lens in visual accommodation.
• Rouget's muscle : the circular portion of the ciliary muscle.
• musculus dilatator pupillae / dilator pupillae muscle : a name given fibers extending radially from the sphincter pupillae to the ciliary margin; innervation, sympathetic; action, dilates iris.
• musculus sphincter pupillae / sphincter muscle of pupil : circular fibers of the iris, innervated by the ciliary nerves (parasympathetic), and acting to contract the pupil.
• musculi externi bulbi oculi / extraocular muscles / musculi bulbi / muscles of eye / ocular muscles : the 6 voluntary muscles that move the eyeball, including the superior, inferior, middle, and lateral recti, and the superior and inferior oblique muscles
• musculus obliquus inferior bulbi or oculi / inferior oblique muscle of eyeball : origin, orbital plate of maxilla; insertion, sclera; innervation, oculomotor; action, rotates eyeball upward and outward.
• musculus obliquus superior bulbi or oculi / superior oblique muscle of eyeball : origin, lesser wing of sphenoid above optic foramen; insertion, sclera; innervation, trochlear; action, rotates eyeball downward and outward.
• musculus rectus inferior bulbi or oculi / inferior rectus muscle : origin, annulus tendineus communis; insertion, under side of sclera; innervation, oculomotor; action, adducts, rotates eyeball downward and medially.
• musculus rectus lateralis bulbi or oculi / lateral rectus muscle : origin, annulus tendineus communis; insertion, lateral side of sclera; innervation, abducens; action, abducts eyeball.
• musculus rectus medialis bulbi or oculi / medial rectus muscle : origin, annulus tendineus communis; insertion, medial side of sclera; innervation, oculomotor; action, adducts eyeball.
• musculus rectus superior bulbi / superior rectus muscle : origin, annulus tendineus communis; insertion, upper aspect of sclera; innervation, oculomotor; action, adducts, rotates eyeball upward and medially.
• middle ear muscles
• intraauricular muscles / musculi ossiculorum auditoriorum / muscles of auditory ossicles : the 2 muscles of the middle ear :
• musculus stapedius / stapedius muscle : origin, interior of pyramid of tympanic cavity; insertion, posterior surface of neck of stapes; innervation, stapedial branch of facial; action, dampens stapedial movement.
• musculus tensor tympani / tensor muscle of tympanic membrane : origin, cartilaginous portion of auditory tube; insertion, manubrium of malleus; innervation, mandibular; action, tenses tympanic membrane.
• musculi linguae / musculi linguales / lingual muscles / muscles of tongue : the extrinsic and intrinsic muscles that move the tongue
• intrinsic tongue muscles
• musculus longitudinalis inferior linguae / inferior longitudinal muscle of tongue : origin, inferior surface of tongue at base; insertion, tip of tongue; innervation, hypoglossal; action, changes shape of tongue in mastication and deglutition.
• musculus longitudinalis superior linguae / superior longitudinal muscle of tongue : origin, submucosa and septum of tongue; insertion, margins of tongue; innervation, hypoglossal; action, changes shape of tongue in mastication and deglutition.
• musculus verticalis linguae / vertical muscle of tongue : origin, dorsal fascia of tongue; insertion, sides and base of tongue; innervation, hypoglossal; action, changes shape of tongue in mastication and deglutition.
• musculus transversus linguae / transverse muscle of tongue : origin, median septum of tongue; insertion, dorsum and margins of tongue; innervation, hypoglossal; action, changes shape of tongue in mastication and deglutition.
• extrinsic tongue muscles
• musculus geniohyoideus / geniohyoid muscle : origin, mental spine of mandible; insertion, body of hyoid bone; innervation, a branch of first cervical nerve through hypoglossal; action, elevates, draws hyoid forward.
• musculus styloglossus / styloglossus muscle : origin, styloid process; insertion, margin of tongue; innervation, hypoglossal; action, raises and retracts tongue.
• musculus hyoglossus / hyoglossal muscle : origin, body and greater cornu of hyoid bone; insertion, side of tongue; innervation, hypoglossal; action, depresses and retracts tongue.
• musculi colli / cervical muscles / musculi cervicis : the muscles of the neck, including the sternocleidomastoid and the longus colli, and the suprahyoid, infrahyoid, and scalene muscles
• posterior neck muscles
• musculus sternocleidomastoideus / sternocleidomastoid muscle (2 heads): origin, STERNAL HEAD—manubrium sterni, CLAVICULAR HEAD—clavicle; insertion, mastoid process and superior nuchal line of occipital bone; innervation, accessory nerve and cervical plexus; action, flexes vertebral column, rotates head.
• musculus semispinalis / semispinal muscle : a muscle composed of fibers extending obliquely from the transverse processes of the vertebrae to the spine, except for the semispinalis capitis; it includes the m. semispinalis capitis, m. semispinalis cervicis, and m. semispinalis thoracis.
• musculus semispinalis capitis / semispinal muscles of head : origin, transverse processes of five or six upper thoracic and four lower cervical vertebrae; insertion, occipital bone; innervation, suboccipital, greater occipital, and branches of cervical; action, extends head.
• musculus semispinalis cervicis / semispinal muscles of neck : origin, transverse processes of five or six upper thoracic vertebrae; insertion, spinous processes of second to fifth cervical vertebrae; innervation, branches of cervical; action, extends, rotates vertebral column.
• musculus semispinalis dorsi or thoracis / semispinal muscles of thorax : origin, transverse processes of sixth to tenth thoracic vertebrae; insertion, spinous processes of 2 lower cervical and four upper thoracic vertebrae; innervation, spinal nerves; action, extends, rotates vertebral column.
• musculus longissimus / longissimus muscle : the largest element of the m. erector spinae, which includes the m. longissimus capitis, m. longissimus cervicis, and m. longissimus thoracis.
• musculus longisimus capitis / longissimus muscle of head : origin, transverse processes of four or five upper thoracic vertebrae, articular processes of three or four lower cervical vertebrae; insertion, mastoid process of temporal bone; innervation, branches of cervical; action, draws head backward, rotates head.
• musculus longissimus cervicis or colli / longissimus muscle of neck : origin, transverse processes of four or five upper thoracic vertebrae; insertion, transverse processes of second to sixth cervical vertebrae; innervation, lower cervical and upper thoracic; action, extends cervical vertebrae
• musculus longissimus dorsi or thoracis / longissimus muscle of thorax : origin, transverse and articular processes of lumbar vertebrae and thoracolumbar fascia; insertion, transverse processes of all thoracic vertebrae, 9 or 10 lower ribs; innervation, lumbar and thoracic; action, extends thoracic vertebrae.
• musculi ossis hyoidei / muscles of the hyoid bone
• musculi suprahyoidei / suprahyoid muscles : the muscles that attach the hyoid bone to the skull, including :
• musculus digastricus / digastric muscle : origin, VENTER ANTERIOR—digastric fossa on deep surface of inferior border of mandible near symphysis, VENTER POSTERIOR—mastoid notch of temporal bone; insertion, intermediate tendon on hyoid bone; innervation, VENTER ANTERIOR—mylohyoid, VENTER POSTERIOR—digastric branch of facial; action, elevates hyoid bone, lowers jaw.
• musculus genioglossus / genioglossus muscle : origin, mental spine of mandible; insertion, hyoid bone and inferior surface of tongue; innervation, hypoglossal; action, protrudes and depresses tongue.
• musculus mylohyoideus / mylohyoid muscle : origin, mylohyoid line of mandible; insertion, body of hyoid bone and median raphe; innervation, mylohyoid branch of inferior alveolar; action, elevates hyoid bone, supports floor of mouth.
• musculus stylohyoideus / stylohyoid muscle : origin, styloid process; insertion, body of hyoid bone; innervation, facial; action, draws hyoid and tongue superiorly and posteriorly.
• musculi infrahyoidei / infrahyoid muscles : the muscles that anchor the hyoid bone to the sternum, clavicle, and scapula, including ...
• musculus sternohyoideus / sternohyoid muscle : origin, manubrium sterni and clavicle; insertion, body of hyoid bone; innervation, upper ansa cervicalis; action, depresses hyoid bone and larynx.
• cleidohyoid muscle : a slip of muscle sometimes seen augmenting the sternohyoid muscle, extending from the hyoid bone to the clavicle.
• musculus thyrohyoideus / thyrohyoid muscle : origin, lamina of thyroid cartilage; insertion, greater cornu of hyoid bone; innervation, first cervical; action, raises and changes form of larynx.
• musculus omohyoideus / omohyoid muscle , comprising 2 bellies (superior and inferior) connected by a central tendon that is bound to the clavicle by a fibrous expansion of the cervical fascia; origin, superior border of scapula; insertion, lateral border of hyoid bone; innervation, upper cervical through ansa cervicalis; action, depresses hyoid bone.
• musculus sternothyroideus / sternothyroid muscle : origin, manubrium sterni; insertion, lamina of thyroid cartilage; innervation, ansa cervicalis; action, depresses thyroid cartilage.
• musculus levator glandulae thyroideae / levator muscle of thyroid gland : an inconstant muscle originating on the isthmus or pyramid of the thyroid gland and inserting on the body of the hyoid bone.
• pectoral girdle muscles
• anterior pectoral girdle muscles
• musculus serratus anterior / anterior serratus muscle : origin, eight or nine upper ribs; insertion, medial border of scapula; innervation, long thoracic; action, draws scapula forward; rotates scapula to raise shoulder in abduction of arm.
• musculus pectoralis minor / smaller pectoral muscle : origin, third, fourth, and fifth ribs; insertion, coracoid process of scapula; innervation, lateral and medial pectoral; action, draws shoulder forward and downward, raises third, fourth, and fifth ribs in forced inspiration.
• musculus subclavius / subclavius muscle : origin, first rib and its cartilage; insertion, lower surface of clavicle; innervation, fifth and sixth cervical; action, depresses lateral end of clavicle.
• posterior pectoral girdle muscles
• musculus trapezius / trapezius muscle : origin, occipital bone, ligamentum nuchae, spinous processes of seventh cervical and all thoracic vertebrae; insertion, clavicle, acromion, spine of scapula; innervation, accessory nerve and cervical plexus; action, rotates scapula to raise shoulder in abduction of arm, draws scapula backward.
• musculus levator scapulae / levator muscle of scapula : origin, transverse processes of four upper cervical vertebrae; insertion, medial border of scapula; innervation, third and fourth cervical; action, raises scapula.
• musculus rhomboideus / rhomboid muscle
• musculus rhomboideus major / greater rhomboid muscle : origin, spinous processes of second, third, fourth, and fifth thoracic vertebrae; insertion, medial margin of scapula; innervation, dorsal scapular; action, retracts, elevates scapula.
• musculus rhomboideus minor / lesser rhomboid muscle : origin, spinous processes of seventh cervical to first thoracic vertebrae, lower part of ligamentum nuchae; insertion, medial margin of scapula at root of the spine; innervation, dorsal scapular; action, adducts, elevates scapula.
• musculi extremitatis or membri superioris / muscles of superior limb : the muscles acting on the arm, forearm, and hand.
• move humerus
• scapular muscles
• musculus deltoideus / deltoid muscle : origin, clavicle, acromion, spine of scapula; insertion, deltoid tuberosity of humerus; innervation, axillary; action, abducts, flexes, extends arm.
• musculus supraspinatus / supraspinous muscle : origin, supraspinous fossa of scapula; insertion, greater tubercle of humerus; innervation, suprascapular; action, abducts humerus.
• musculus infraspinatus / infraspinous muscle : origin, infraspinous fossa of scapula; insertion, greater tubercle of humerus; innervation, suprascapular; action, rotates humerus laterally.
• musculus teres major / teres major muscle : origin, inferior angle of scapula; insertion, crest of intertubercular sulcus of humerus; innervation, lower subscapular; action, adducts, extends, rotates arm medially.
• musculus teres minor / teres minor muscle : origin, lateral margin of scapula; insertion, greater tuberosity of humerus; innervation, axillary; action, rotates arm laterally.
• musculus subscapularis / subscapular muscle : origin, subscapular fossa of scapula; insertion, lesser tubercle of humerus; innervation, subscapular; action, rotates humerus medially.
• musculus coracobrachialis / coracobrachial muscle : origin, coracoid process of scapula; insertion, medial surface of shaft of humerus; innervation, musculocutaneous; action, flexes, adducts arm.
• axial muscles
• musculus pectoralis major / greater pectoral muscle : origin, clavicle, sternum, six upper ribs, aponeurosis of obliquus externus abdominis. These origins are reflected in the subdivision of the muscle into clavicular, sternocostal, and abdominal parts; insertion, crest of intertubercular groove of humerus; innervation, medial and lateral pectoral; action, adducts, flexes, rotates arm medially.
• Sibson's groove : a furrow sometimes seen at the lower border of the pectoralis major muscle.
• musculus latissimus dorsi : origin, spines of lower thoracic vertebrae, lumbar and sacral vertebrae through thoracolumbar fascia, iliac crest, lower ribs, inferior angle of scapula; insertion, floor of intertubercular sulcus of humerus; innervation, thoracodorsal; action, adducts, extends, and rotates humerus medially. Used in dynamic cardiomyoplasty
• Chassaignac's axillary muscle : an occasional muscle bundle extending from the lower edge of the latissimus dorsi across the hollow of the axilla to the brachial fascia or to the lower border of the pectoralis minor
• axillary arch : a muscular slip occasionally arising from the cranial border of the latissimus dorsi muscle, crossing the axilla ventral to the axillary vessels and nerves, and joining the under surface of the tendon of the pectoralis major, the coracobrachialis, or the fascia of the biceps brachii muscle.
• move forearm
• musculus biceps brachii / biceps muscle of arm (2 heads) : origin, CAPUT LONGUM—upper border of glenoid cavity, CAPUT BREVE—apex of coracoid process; insertion, radial tuberosity and fascia of forearm; innervation, musculocutaneous; action, flexes forearm, supinates hand.
• musculus brachialis / brachial muscle : origin, anterior surface of humerus; insertion, coronoid process of ulna; innervation, radial, musculocutaneous; action, flexes forearm.
• musculus brachioradialis / brachioradial muscle : origin, lateral supracondylar ridge of humerus; insertion, lower end of radius; innervation, radial; action, flexes forearm.
• musculus triceps brachii / triceps muscle of arm (3 heads) : origin, CAPUT LONGUM—infraglenoid tubercle of scapula, CAPUT LATERALE—posterior surface of humerus, lateral border of humerus, lateral intermuscular septum, CAPUT MEDIALE—posterior surface of humerus below radial groove, medial border of humerus, medial intermuscular septa; insertion, olecranon of ulna; innervation, radial; action, extends forearm, long head adducts and extends arm.
• wrist, hand, fingers
• musculus supinator / supinator muscle : origin, lateral epicondyle of humerus, ulna, elbow joint fascia; insertion, radius; innervation, deep radial; action, supinates hand.
• musculus pronator teres (2 heads): origin, CAPUT HUMERALE—medial epicondyle of humerus, CAPUT ULNARE— coronoid process of ulna; insertion, lateral surface of radius; innervation, median; action, pronates hand and flexes elbow.
• musculus pronator quadratus : origin, anterior surface and border of distal third or fourth of ulna; insertion, anterior surface and border of distal fourth of shaft of radius; innervation, anterior interosseous; action, pronates hand.
• musculus flexor carpi radialis / radial flexor muscle of wrist : origin, medial epicondyle of humerus; insertion, base of second metacarpal; innervation, median; action, flexes and abducts wrist joint.
• musculus flexor carpi ulnaris / ulnar flexor muscle of wrist (2 heads): origin, CAPUT HUMERALE—medial epicondyle of humerus, CAPUT ULNARE—olecranon, ulna, intermuscular septum; insertion, pisiform, hook of hamate, proximal end of fifth metacarpal; innervation, ulnar; action, flexes and adducts wrist joint.
• musculus flexor digiti minimi or quinti brevis manus / short flexor muscle of little finger : origin, hook of hamate bone, transverse carpal ligament; insertion, medial side of proximal phalanx of little finger; innervation, ulnar; action, flexes little finger.
• musculus flexor digitorum profundus / deep flexor muscle of fingers : origin, shaft of ulna, coronoid process; insertion, distal phalanges of fingers; innervation, ulnar and anterior interosseous; action, flexes distal phalanges.
• musculus flexor digitorum superficialis or sublimis / superficial flexor muscle of fingers (2 heads): origin, CAPUT HUMEROULNARE—medial epicondyle of humerus, coronoid process of ulna, CAPUT RADIALE— oblique line of radius, anterior border; insertion, middle phalanges of fingers; innervation, median; action, flexes middle phalanges.
• musculus flexor pollicis longus / long flexor muscle of thumb : origin, anterior surface of radius and coronoid process of ulna; insertion, base of distal phalanx of thumb; innervation, anterior interosseous; action, flexes thumb.
• musculus extensor carpi radialis brevis / short radial extensor muscle of wrist : origin, lateral epicondyle of humerus, insertion, base of third metacarpal bone; innervation, radial; action, extends and abducts wrist joint.
• musculus extensor carpi radialis longus / long radial extensor muscle of wrist : origin, lateral supracondylar ridge of humerus; insertion, base of second metacarpal bone; innervation, radial; action, extends and abducts wrist joint.
• musculus extensor carpi ulnaris / ulnar extensor muscle of wrist (2 heads): origin, CAPUT HUMERALE—lateral epicondyle of humerus, CAPUT ULNARE—dorsal border of ulna; insertion, base of fifth metacarpal bone; innervation, deep radial; action, extends and adducts wrist joint.
• musculus extensor digiti minimi or quinti proprius / extensor muscle of little finger : origin, common extensor tendon; insertion, tendon of extensor digitorum to little finger; innervation, deep radial; action, extends little finger.
• extensor digitorum superficialis (-> middle phalanges)
• musculus extensor digitorum (communis) / extensor muscle of fingers : origin, lateral epicondyle of humerus; insertion, common extensor tendon of each finger; innervation, posterior interosseus; action, extends wrist joint and phalanges.
• musculus extensor pollicis brevis / short extensor muscle of thumb : origin, dorsal surface of radius and interosseous membrane; insertion, dorsal surface of proximal phalanx of thumb; innervation, posterior interosseous; action, extends thumb.
• musculus extensor pollicis longus / long extensor muscle of thumb : origin, dorsal surface of ulna and interosseous membrane; insertion, dorsal surface of distal phalanx of thumb; innervation, posterior interosseous; action, extends, abducts thumb.
• musculus extensor indicis (proprius) / extensor muscle of index finger : origin, dorsal surface of body of ulna, interosseous membrane; insertion, common extensor tendon of index finger; innervation, posterior interosseous; action, extends index finger.
• extensor digitorum profundus (-> distal phalanges)
• intrinsic muscles of hand
• thenar muscles : the abductor and flexor muscles of the thumb
• musculus abductor pollicis brevis / short abductor muscle of thumb : origin, scaphoid, ridge of trapezium, transverse carpal ligament; insertion, lateral surface of base of proximal phalanx of thumb; innervation, median; action, abducts thumb.
• musculus abductor pollicis longus / long abductor muscle of thumb : origin, posterior surfaces of radius and ulna; insertion, radial side of base of first metacarpal bone; innervation, posterior interosseous; action, abducts, extends thumb.
• musculus flexor pollicis brevis / short flexor muscle of thumb : origin, flexor retinaculum, ridge of trapezium; insertion, base of proximal phalanx of thumb; innervation, median, ulnar; action, flexes and adducts thumb.
• hypothenar muscles : the intrinsic muscles of the little finger; flexing, abducting, and opposing it, and comprising the palmaris brevis, abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi.
• musculus abductor digiti minimi or quinti manus / abductor muscle of little finger : origin, pisiform bone, flexor carpi ulnaris tendon; insertion, medial surface of base of proximal phalanx of little finger; innervation, ulnar; action, abducts little finger.
• musculus adductor pollicis / adductor muscle of thumb (2 heads): origin, CAPUT OBLIQUUM—sheath of flexor carpi radialis, anterior carpal ligament, capitate bone, and bases of second and third metacarpals, CAPUT TRANSVERSUM—lower two-thirds of anterior surface of third metacarpal; insertion, medial surface of base of proximal phalanx of thumb; innervation, ulnar; action, adducts, opposes thumb.
• musculi interossei dorsales manus / dorsal interosseous muscles of hand (4): origin, by two heads from adjacent sides of metacarpal bones; insertion, extensor tendons of second, third, and fourth fingers; innervation, ulnar; action, abduct, flex proximal phalanges.
• musculi interossei palmares or volares / palmar interosseous muscles (3): origin, sides of second, fourth, and fifth metacarpal bones; insertion, extensor tendons of second, fourth, and fifth fingers; innervation, ulnar; action, adduct, flex proximal phalanges, extend middle and distal phalanges.
• musculus opponens digiti minimi or quinti / opposing muscle of little finger : origin, hook of hamate bone, transverse carpal ligament; insertion, medial aspect of fifth metacarpal; innervation, eighth cervical through ulnar; action, rotates, abducts, and flexes fifth metacarpal.
• musculus opponens pollicis / opposing muscle of thumb : origin, ridge of trapezium, flexor retinaculum; insertion, radial side of first metacarpal; innervation, sixth and seventh cervical through median; action, flexes and opposes thumb.
• musculus palmaris brevis / short palmar muscle : origin, palmar aponeurosis; insertion, skin of medial border of hand; innervation, ulnar; action, assists in deepening hollow of palm.
• musculus palmaris longus / long palmar muscle : origin, medial epicondyle of humerus; insertion, flexor retinaculum, palmar aponeurosis; innervation, median; action, flexes wrist joint.
• musculi lumbricales manus / lumbrical muscles of hand : origin, tendons of flexor digitorum profundus; insertion, extensor tendons of four lateral fingers; innervation, median and ulnar; action, flex metacarpophalangeal joint and extend middle and distal phalanges.
Functional posture of the hand :
• hook grip : that usually assumed when grasping handles or straps or suspending or pulling upon an object: the fingers are flexed toward the palm, to a degree depending on the size of the grasped object.
• power grip : that usually assumed when holding a hammer or piece of rope: the fingers are flexed around an object, with counter pressure from the thumb, which is positioned to bring either its pad or its medial border firmly against the held object.
• precision grip : that usually assumed when holding a pen or pencil: the object is grasped between the tips of the thumb and fingers (most often the index, with the middle often involved).
• respiration
• inspiratory muscles : the muscles that act during inspiration, such as the diaphragm, and the intercostal and pectoral muscles.
• thoracic or respiratory diaphragm / phren / midriff / diaphragmatic muscle / diaphragma thoraco-abdominale : the musculomembranous partition separating the abdominal and thoracic cavities, and serving as a major thoracic muscle
• hiatus aorticus / aortic hiatus : the opening in the diaphragm through which the aorta and thoracic duct pass
• hiatus oesophageus / esophageal hiatus : the opening in the diaphragm for the passage of the esophagus and the vagus nerves
• hiatus pleuroperitonealis / foramen of Bochdalek : a posterolateral opening in the fetal diaphragm; its failure to close leaves a congenital posterolateral defect which may become a site for congenital diaphragmatic hernia
• trefoil tendon / centrum tendineum [diaphragmatis] / central tendon of diaphragm / cordiform ligament of diaphragm, and phrenic center : the cloverleaf-shaped aponeurosis, immediately below the pericardium, onto which the diaphragmatic fibers converge to insert

• musculi intercostales externi / external intercostal muscles (11 on each side): origin, inferior border of rib; insertion, superior border of rib below; innervation, intercostal; action, draw ribs together in respiration and expulsive movements.
• musculi intercostales interni / internal intercostal muscles (11 on each side): origin, inferior border of rib and costal cartilage; insertion, superior border of rib and costal cartilage below; innervation, intercostal; action, draw ribs together in respiration and expulsive movements.
• musculi intercostales intimi / innermost intercostal muscles : the layer of muscle fibers separated from the internal intercostal muscles by the intercostal nerves.
• musculi levatores costarum / levator muscles of ribs (12 on each side): originating from the transverse processes of the seventh cervical and first to eleventh thoracic vertebrae and inserting medial to the angle of a lower rib (see musculi levatores costarum breves and musculi levatores costarum longi); innervated by intercostal nerves and aiding in elevation of the ribs in respiration.
• musculi levatores costarum breves / short levator muscles of ribs : the levatores costarum muscles of each side that insert medial to the angle of the rib next below the vertebra of origin.
• musculi levatores costarum longi / long levator muscles of ribs : the lower levatores costarum muscles of each side, which have fascicles extending down to the second rib below the vertebra of origin.
• musculi abdominis : the muscles of the abdomen.
• musculus obliquus externus abdominis / external oblique muscle of abdomen ; origin, lower eight ribs at costal cartilages; insertion, crest of ilium, linea alba through rectus sheath; innervation, lower intercostal; action, flexes and rotates vertebral column, compresses abdominal viscera.
• anulus inguinalis subcutaneus or superficialis / superficial or external inguinal ring : an opening in the aponeurosis of the external oblique muscle for the spermatic cord or for the round ligament. Located at pubic tubercle. Occurs just above inguinal ligament
• crus mediale anuli inguinalis superficialis / medial crus of superficial inguinal ring / superior crus of subcutaneous inguinal ring / crus superius anuli inguinalis subcutanei / anterior or internal crus of anterior inguinal ring / anterior or internal inguinal ligament : the part of the superficial inguinal ring that is attached to the symphysis and that blends with the fundiform ligament of the penis
• crus laterale anuli inguinalis superficialis / lateral crus of superficial inguinal ring / crus inferius annuli inguinalis subcutanei / external or posterior crus of anterior inguinal ring : the part of the superficial inguinal ring that blends with the inguinal ligament as it goes to the pubic tubercle
• fibrae intercrurales / intercrural fibers / Cooper's or Scarpa's fascia / Todd's process / collateral fibers of Winslow : fibers joining the medial and lateral crura of the superficial inguinal ring
• Buck's fascia : the deep fascia of the penis, being continuous with Colles' fascia of the perineum and with Scarpa's fascia of the abdominal wall
• musculus obliquus internus abdominis / internal oblique muscle of abdomen : origin, inguinal ligament, iliac crest, thoracolumbar fascia; insertion, inferior 3 or 4 costal cartilages, linea alba, conjoined tendon to pubis; innervation, lower intercostal; action, flexes and rotates vertebral column, compresses abdominal viscera.
• cremasteric fascia / fascia cremasterica / Cooper's fascia / intercolumnar fascia : the thin covering of the spermatic cord formed by the investing fascia of the cremasteric muscle; it is adjacent to the external surface of the internal spermatic fascia
• musculus transversus abdominis / transverse abdominal muscle : origin, cartilages of 6 lower ribs, thoracolumbar fascia, iliac crest, inguinal ligament; insertion, linea alba through rectus sheath, conjoined tendon to pubis; innervation, lower intercostals, iliohypogastric, ilioinguinal; action, compresses abdominal viscera.
• musculus rectus abdominis : origin, pubis; insertion, xiphoid process, cartilages of fifth, sixth, and seventh ribs; innervation, branches of lower thoracic; action, flexes lumbar vertebrae, supports abdomen.
• rectoabdominal fascia / vagina musculi recti abdominis / rectus sheath : sheath of rectus abdominis muscle: a sheath formed by the aponeuroses of other abdominal muscles, within which the rectus abdominis can move
• linea alba (abdominis) / white line : the tendinous median line on the anterior abdominal wall between the two rectus muscles, formed by the decussating fibers of the aponeuroses of the three flat abdominal muscles.
• anulus umbilicalis / umbilical canal or ring : the aperture in the abdominal wall through which the umbilical cord communicates with the fetus. After birth it is felt for some time as a distinct fibrous ring surrounding the umbilicus; these fibers later shrink progressively
• Scarpa's fascia : the deep, membranous layer of subcutaneous abdominal fascia.
• Richet's fascia : a fold of extraperitoneal fascia enveloping the obliterated umbilical vein.
• fossa iliacosubfascialis / Biesiadecki's iliacosubfascial fossa : an inconstant depression on the inner surface of the abdomen between the psoas muscle and the crest of the ilium
• fossa iliopectinea / iliopectineal fossa / lesser fossa of Scarpa : a depression between the iliopsoas and pectineus muscles in the center of the femoral triangle
• fascia transversalis / endoabdominal, internal abdominal or transverse fascia : part of the inner investing layer of the abdominal wall, continuous with the fascia of the other side behind the rectus abdominis and the rectus sheath, and continuous also with the diaphragmatic fascia, the iliac fascia, and the parietal pelvic fascia
• Hesselbach's ligamentum interfoveolare / interfoveolar ligament : a thickening in the transversalis fascia on the medial side of the deep inguinal ring; it is connected above to the transversus muscle and below to the inguinal ligament.
• anulus inguinalis profundus / deep or internal abdominal or inguinal ring / anulus abdominalis abdominis / anulus inguinalis abdominalis : an aperture in the fascia transversalis for the spermatic cord or for the round ligament. Landmark: middle of Malgaignes's line
• tractus iliopubicus / iliopubic tract / deep crural arch : a thickened band of tissue that strengthens the lower part of the deep inguinal ring and forms the base of the internal spermatic fascia
• fascia spermatica interna / internal spermatic fascia : the thin innermost covering of the spermatic cord, derived from the transversalis fascia of the abdominal wall
• Bogros' retroinguinal space : a region bounded by the peritoneum above and the fascia transversalis below, in which the lower part of the external iliac artery can be found without cutting the peritoneum
• subperitoneal or extraperitoneal fascia / fascia extraperitonealis or subperitonealis / extraperitoneal tissue : the thin layer of areolar connective tissue separating the parietal peritoneum from the abdominal walls
• fusion fascia : a double connective tissue band derived from the fusion of closely apposed surfaces of peritoneum as a result of degeneration of the lubricating serous layer between them; such fasciae are seen in the pelvic and abdominal cavities where crowding of organs occurs
• thoracic fascia / external intercostal fascia / fascia thoracica : the deep fascia that covers the outside of the thoracic cavity
• fascia lumbodorsalis or thoracolumbalis / lumbodorsal or thoracolumbar fascia : the fascia of the back that attaches medially to the spinous processes of the vertebral column for its entire length and blends laterally with the aponeurosis of the transversus abdominis muscle; inferiorly it attaches to the iliac crest and the sacrum
• canalis inguinalis / inguinal canal / abdominal canal / Velpeau's canal : the passage (5 cm in length) superficial to the deep inguinal ring for transmission of the spermatic cord in the male (see descent of testis) and the round ligament of uterus in the female. The fibers of external oblique muscle aponeurosis create the pillars of the outer ring of the inguinal canal.
• anterior wall : aponeurosis of external oblique muscle
• posterior wall : fascia trasversalis
• superior wall : internal oblique and transverse muscle (joint tendon)
• inferior wall : inguinal ligament


Horizontal section of the abdominal wall at the level of the right inguinal canal :

Seen from the internal abdomne, the peritoneal surface of the inguinal wall presents fold converging from the pelvis towards the navel :
• the median fold is the remnant of the urachus
• laterally there is the fold of the remnant of the umbilical artery
• more laterally there is the epigastric vessel fold
Such folds border bilaterally 3 foveae :
• fossa or fovea inguinalis lateralis / external or lateral inguinal fovea or fossa : the depression on the inside of the anterior abdominal wall lateral to the lateral umbilical fold, corresponding to the internal inguinal ring and placed laterally to the fold of epigastric vessels, through which occur the external oblique inguinal hernias.
• fossa or fovea inguinalis media / middle inguinal fovea or fossa, placed between epigastric (lateral) vessels and the remnant of the umbilical artery (medial), corresponding to Hesselbach's trigonum inguinale / inguinal triangle : the triangular area on the anteroinferior abdominal wall bounded by the rectus abdominis muscle, the inguinal ligament, and the inferior epigastric vessels: the site in which a direct inguinal hernia begins
• fossa or fovea inguinalis medialis / internal or medial inguinal fovea or fossa : the depression on the inside of the anterior abdominal wall between the medial and lateral umbilical folds, placed between the remnant of the urachus (medial) and the remnant of the umbilical artery (lateral), crossed by internal oblique inguinal hernias. The inner foveola is reenforced by the conjoined tendon of transverse and internal oblique muscle and the rectus muscle; that explains the relative rarity of the internal oblique inguinal hernia
• epigastric or urachal fossa : a depression on the inner surface of the anterior abdominal wall, between the urachus and the hypogastric artery
• trigonum femorale / femoral triangle / Scarpa's triangle : a triangular subfascial area bounded superiorly by the inguinal ligament, laterally by the medial border of the sartorius muscle, and medially by the medial border of the adductor longus muscle