Acetabulum

“ The ilia are prolonged forwards, in front of the acetabulum, as well as behind it; and the resemblance to the bird's ilium thus produced is greatly increased by the widely arched form of the acetabular margin of the bone, and the extensive perforation of the floor of the actabulum. ”

“ When the bone has reached the edge of the acetabulum, a second assistant slips the doubled jack-towel over his shoulders, and by raising his body, lifts the femur away from the brim of the acetabulum, while the surgeon, grasping the foot and knee, makes a few movements of rotation backwards and forwards to ease the head into its socket. ”

“ I suspect that the ilium is broken in the middle, and, as a consequence, that the distance from the posterior to the anterior ends of the visible parts of the bone (6⋅6 inch) is somewhat greater than it should be. Hence the acetabulum probably appears to be longer than it naturally is. The postacetabular process (c) , which should articulate with the ischium, is swollen and thick, but thins off, above and behind, into a thin vertical plate, the posterior curved margin of which is broad and turned in, like a narrow shelf. ”

“ It forms a small part of the anterior wall of the acetabulum.
The epipubis (4) is a slightly arched bone, somewhat enlarged at its proximal end where it unites with the ischium, and flattened out into a fan-shaped extremity, where it is united with its fellow and with the last pair of abdominal ribs by the broad, thin sheet of cartilage or fibrous tissue noted in connection with the abdominal ribs. As mentioned above, it is called by Wiedersheim and others the pubis. Near the center of the acetabulum there is a small foramen. ”

“ III, pubis. a, crest of the ilium; b, posterior inferior spine; c, great sciatic notch; d, acetabulum; d′, incisura acetabuli; e, spine of the ischium; f, lesser sciatic notch; g, tuberosity of the ischium; h, ramus of the ischium; i, ramus of the pubis; j, obturator foramen; k, pubic tubercle; l, iliopectineal line; l′, ilio-pectineal eminence; m, anterior superior process.
The ilium (I) is somewhat contracted at the middle and broader at its ends. One end enters into the acetabulum (Fig. 55, d) and forms about one-fifth the articular surface. This end is also the thickest part of the bone. ”

“ At the upper end is the hemispherical head, which is set upon a distinct neck and projects inward and upward, fitting into the acetabulum of the hip-bone. Nearly all land mammals have a small pit on the head of the femur, in which is inserted one end of the round ligament, while the other end is attached in a corresponding depression in the floor of the acetabulum. ”

“ No proper new bony socket forms like that in traumatic dislocations that remain unreduced because in the congenital variety the thickened capsule intervenes between the head of the bone and the dorsum ilii. The displacement of the head is most frequently backwards (dorsal luxation) , and as the point of support thus falls behind the acetabulum the pelvis tilts forwards, and the lumbar spine becomes unduly concave (lordosis) . ”

“ Primates. In Man and the Anthropoid Apes the pelvis is very large and wide, and the ilium has much expanded iliac and gluteal surfaces. The symphysis is rather short and formed by the pubis alone. The acetabulum is deep and the obturator foramen large, and there is frequently a well-marked ischial tuberosity. ”

“ The os innominatum.—Fracture of the ilium may be observed either at the angle of the hip or at the neck of the bone; those of the pubes may take place at the symphysis, or in the body of the bone; those of the ischium on the floor of the bone, or at its posterior external angle. Or, again, the fracture may involve all three of these constituent parts of the hip bone by having its situation in the articular cavity—the acetabulum by which it joins the femur or thigh bone. ”

“ The broadening of the trochanteric region is greater, and the great trochanter is approximated to the acetabulum.
Prognosis.—The risks to life in the aged are similar to those of intra-capsular fracture. In youths and healthy adults the chief danger is that the limb may be shortened and its function thereby impaired.
As the periosteum and retinacular ligaments which transmit the blood vessels to the proximal fragments are intact, bony union is the rule. ”

“ The details of incisions for such an operation need scarcely be given, as they must vary in each case with the amount of bone diseased, and the position of the already existing sinuses. The amount of bone that may be removed varies much. Erichsen in one case excised "the upper end of the femur, the acetabulum, the rami of the pubis, and of the ischium, a portion of the tuber ischii, and part of the dorsum ilii." ”

“ Ventral to the pubic articulation the ischial blade is broad and thin, bending laterally toward the distal margin. The distal margin of the ischial blade bends abruptly in a medio-ventral direction. The acetabulum is large and curved cranio-ventrally toward the pubic peduncle. The caudal margin of the ischial blade is long and curved cranially. A distinct triangular process projects medially from the mid-line of the caudal margin of the main ischial blade. The puboischial contact is estimated to be half of the pubis length, where the ischial blade is shorter than the pubic blade. ”

“ The FEMUR is the longest bone in the system. It supports the weight of the head, trunk, and upper extremities. The large, round head of this bone is placed in the acetabulum. This articulation is a perfect specimen of the ball and socket joint.
107. The PATELLA is a small bone connected with the tibia by a strong ligament. The tendon of the ex-tens ́or muscles of the leg is attached to its upper edge. This bone is placed on the anterior part of the lower extremity of the femur, and acts like a pulley, in the extension of the limb. ”

“ The bones of the female are lighter, softer, and more elegantly shaped than those of the male. The female head is smaller, the pelvis is broader and deeper, and the cavity of the acetabulum less deeply sunk than in man. ”

“ The thoracic ribs articulate with the long transverse processes, and sternal ribs and [211] abdominal splint ribs (fig. 46, 4) occur. The sternum is cartilaginous, and both it and the shoulder-girdle are very simple. The precoracoid is represented by merely a small process on the coracoid, while the clavicles are absent, except in the Parasuchia. In the pelvis (fig. 49) there is a large ilium, and an ischium meeting its fellow in a ventral symphysis; these two bones form almost the whole of the acetabulum. ”

“ Fig. 65.—Skeleton of Wallaby (Macropus ualabatus) . The scapula is raised somewhat higher than in nature. The end of the tail is omitted. The head of the femur has been separated from the acetabulum. acet, Acetabulum; acr, acromion process; ast, astragalus; cal, calcaneum; cbd, cuboid; chev, chevron-bones; cl, clavicle; cun, cuneiform of carpus; epi, epipubis; fb, fibula; fem, femur; hd, head of femur; hu, humerus; il, ilium; isch, ischium; obt, obturator-foramen; orb, orbit; pis, pisiform; pub, pubis; rad, radius; rb1, first rib; rb13, last rib; sc, scapula; st, sternum; tb, tibia ”

“ The ilium (Fig. 28, 1) is a heavy bone with [85] a dorso-laterally projecting crest; medially it is firmly united to the sacral ribs (Fig. 18, 5) while its outer side forms the upper and greater part of the acetabulum. Its outer and lower border has two surfaces, the larger and more posterior articulating with the ischium, the other with the cartilaginous pubis.
Fig. 28. Pelvis and Sacrum of an Alligator (Caiman latirostris) . ×1⁄2. (Brit. Mus.) (After Reynolds.)
1. ilium. 2. ischium. 3. true pubis. 4. epipubis (so-called pubis) . 5. acetabular foramen. 6. neural spines of sacral vertebrae. ”

“ Between it and the spina lumbalis there is a broad furrow, the bottom of which is formed by the dorsal surface of the lumbar vertebræ. The sulcus ilio-lumbalis dorsalis is formed by the rims of the ilia, so that a ridge is observable. The cavum ilio-lumbale dorsale is formed by the iliac rims on either side. Anteriorly is the canalis ilio-lumbalis, which is formed by the ilium and the lumbar vertebral spines. It is located longitudinally to the vertebræ. The anterior opening of this canal is the larger. Posterior to the acetabulum is the post-acetabular ridge. ”

“ This bar meets and unites with its fellow ventrally before becoming converted into true cartilage, and though the iliac process (il) is never very considerable, yet it is better developed in the embryo than in the adult, and is at first directed nearly horizontally forwards.
Amphibia and Amniota. The primitive cartilaginous pelvic [Pg 607] girdle of the higher types exhibits the same division as that of Pisces into a dorsal and a ventral section, which meet to form the articular cavity for the femur, known as the acetabulum. ”

“ Cervical vertebrae, or those between the skull and the first vertebra which is connected with the sternum by a pair of complete ribs. The last 1 to 5 of these vertebrae have movable ribs which do not reach the sternum, and are called cervico-dorsals. (2) Dorsals, those which begin with the first thoracic rib, and end at the last that is not fused with the ilium. The term “lumbar” vertebrae is inapplicable to birds. (3) Pelvic, all those which are fused with the iliac portion of the pelvis, generally a considerable number. (4) Caudal, those which are not connected with the pelvis. ”

“ The last two cervical vertebrae bear long movable ribs which articulate by distinct capitular and tubercular processes, but do not meet the sternum. The thoracic ribs are eight in number, and each is divisible into a vertebral and a sternal portion. The first five thoracic ribs are flattened curved bars of bone, which articulate by a prominent capitulum with the centrum of the corresponding vertebra, and by a tuberculum with the transverse process. Projecting backwards from each is a large hooked uncinate process. ”