CHAPTEK XL 



• DISSECTION OF THE PELVIS. 



Undeb this heading there will be described not only the pelvic cavity 

 and its contents, but also the tail and the hip-joint. 



Directions. — The dissection of the abdomen having been completed, 

 the vertebral column should be sawn across or disarticulated about the 

 middle of the lumbar region. If the directions given on page 70 have 

 been attended to, the dissector of the pelvis should find the hip-joint 

 intact, with the femur sawn across below the small trochanter, as in 

 Fig. 54 (p. 374). The muscles or portions of muscles left around the 

 hip-joint should be carefully removed, and the ligaments of the joint 

 are to be dissected, noticing in the first place, however, its movements. 



THE HIP-JOINT AND THE LIGAMENTS OF THE PELVIS. 



The HiP-JOiNT belongs to the class of enarthrodial or ball-and-socket 

 joints. 



The bones that enter into its formation are the femur and the os 

 innominatum, the former furnishing a rounded hemispherical head, 

 the latter a cup-like cavity: — the acetabuhim, or cotyloid cavity. 



Movements. If the stump of the femur be grasped, it will be found 

 to have a great freedom of movement. Thus, it can he flexed, extended, 

 abducted, adducted, circumducted, and rotated. In flexion the femur is 

 carried forwards so as to diminish the angle formed by that bone and 

 the ilium. For the definition of the other terms see page 44. In the 

 horse the hip-joint admits of a greater range of movement than any 

 other joint of the limbs. The movement of abduction, however, is less 

 free than it is in the other domestic animals, being, as will presently 

 be seen, restricted by the pubio-femoral ligament. 



The joint possesses four ligaments, viz., capsular, cotyloid, pubio- 

 femoral, and round ligaments. 



The Capsulab Ligament has the form of a double-mouthed sac, 

 attached, on the one hand, to the rim of the cotyloid cavity and to the 

 cotyloid ligament, and, on the other hand, to the periphery of the 

 articular head of the femur. It is strengthened in front by an oblique 

 band representing the ilio-femoral ligament of man. Its inner face is 

 lined by the synovial membrane of the joint, while its outer face is 



