50 VETERINARY STATE BOARD 



Describe the sacrum. 



The sacrum is formed by the consolidation of five vertebrae which 

 are closely fused. It articulates, anteriorly, with the last lumbar 

 vertebra, posteriorly, with the first coccygeal bone, and, laterally, 

 with the OS innominata. 



The bone is triangular in shape with a base anteriorly, articulat- 

 ing with the last lumbar vertebra through its body, articular and 

 transverse processes; posteriorly, the apex articulates with the 

 coccyx ; and laterally, the first segment shows a sort of transverse 

 process which has an auricular facet to furnish articulation with 

 the OS innominata. The inferior surface is smooth and shows four 

 intervertebral foramina, and the superior surface shows in its mid- 

 dle the spinous processes which together constitute the sacral spine. 

 On each side of the sacral spine is a groove which is pierced between 

 each segment by the supersacral foramina. 



Name the bones of the pelvis. 



The OS innominatiom, made up of the ilium, pubis and ischium, 

 and the sacrum. 



Describe the cotyloid cavity. 



The cotyloid cavity is a deep excavation which is formed in the 

 middle of the os innominata at the junction of the ilium, pubis and 

 ischium. It is circumscribed by a narrow rim which is notched on 

 the inner side to communicate with the subpubic notch. The deeper 

 portion is roughened for ligamentous insertion. The cavity receives 

 the articulating head of the femur. 



Describe the pelvis. State the difference between the pelvis of the 

 horse and that of the ox. 



The pelvis is a bony cavity in the posterior part of the body, 

 which prolongs the abdominal cavity between the sacrum and the 

 coccygeal vertebrae. It is formed above by the sacrum, laterally 

 by the ilia, but mostly by the sacrosciatic ligament, and below by 

 the ischia and pubes. The inlet is bounded by the sacrum, pubes 

 and ilia and has four diameters, vertical, horizontal and two 

 oblique; the outlet, through which pass the rectum and genital 

 organs, is bounded by the sacrum, ischia and sacrosciatic ligament, 

 and has two diameters, vertical and horizontal. 



In the ox, the os innominatum is nearly horizontal, the transverse 

 diameter is relatively less extensive, and the ilium is more oblique. 

 Name the bones of the hind limb. 



The OS innominatum or coxa (composed of ilium, pubis and 

 ischium), femur, tibia, fibula, the tarsus (composed of six bones, 



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