_a_, Cranium; _b_, face; _c_, mandible; _1H-7H_, cervical vertebræ;
_13B_, last thoracic vertebra; _1L-7L_, lumbar vertebræ; _K_,
sacrum; _S_, coccygeal vertebræ; _1R-13R_, ribs; _R.Kn._, costal
cartilages; _St._, sternum; _d_, scapula; _d′_, supraspinous fossa;
_d″_, infraspinous fossa; _1_, spine of scapula; _2_, acromion; _3_,
tuberosity of scapula; _3′_, articular end of scapula; _e_, humerus;
_4_, head of humerus; _5_, external tuberosity of humerus; _5′_,
deltoid ridge; _6_, _6′_, epicondyles of humerus; _7_, external
condyloid crest; _7′_, coronoid fossa; _f_, radius; _g_, ulna; _8_,
olecranon; _9_, “beak” of ulna; _h_, carpus; _i_, metacarpus; _k_,
proximal phalanges; _l_, middle phalanges; _m_, distal phalanges;
_n_, sesamoid; _p_, ilium; _10_, wing of ilium; _11_, shaft of
ilium; _12_, crest of ilium; _13_, external angle of ilium (tuber
coxæ); _14_, internal angle of ilium (tuber sacrale); _15_, superior
ischiatic spine; _q_, pubis; _r_, ischium; _16_, tuber ischii; _17_,
acetabulum; _s_, femur; _18_, head of femur; _19_, trochanter major;
_20_, trochanter minor; _21_, trochanter tertius; _22_, _23_,
condyles; _24_, _25_, epicondyles; _26_, trochlea; _t_, patella;
_u_, tibia; _27_, tuberosity of tibia; _28_, _29_, condyles of
tibia; _30_, internal malleolus; _v_, fibula; _31_, external
malleolus; _32_, head of fibula; _w_, tarsus; _x_, metatarsus; _y_,
phalanges; _33_, occipital bone; _34_, paramastoid (styloid)
process; _35_, parietal bone; _36_, frontal bone; _37_, lacrimal
bone; _38_, malar bone; _39_, squamous temporal; _40_, maxilla;
_40′_, infraorbital foramen; _41_, premaxilla; _42_, nasal bone;
_43_, external auditory meatus; _44_, canine tooth; _45_, masseteric
fossa; _46_, angular process of mandible. (After Ellenberger, in
Leisering’s Atlas.)
]
The =sacrum= results from the early fusion of three vertebræ. It is
short, wide, and quadrangular. The spines are fused to form a median
crest, which is notched, however, between the summits of the spines. On
either side are two tubercles, vestiges of the fused articular
processes. The pelvic surface is deeply concave and presents two pairs
of foramina. The wings are prismatic and very high. Their lateral
surfaces are extensive, face almost directly outward, and bear an
auricular surface on the lower part. The anterior surface of the body of
the first vertebra is extensive, depressed in its middle, and bears a
prominent lip below. The anterior articular processes are large and have
extensive, slightly concave facets which face upward and inward. The
posterior articular processes are small. The transverse processes of the
last vertebra project backward and may articulate or fuse with those of
the first coccygeal. The sacral canal is strongly compressed
dorso-ventrally.
[Illustration: