HIP JOINT 329 



by the proximal portion of the ilio-femoral ligament and the upper part 

 of the capsule. Rotation medially tightens the ischio-capsular ligament, and 

 is therefore, in a measure, restrained by it. Rotation laterally is limited by 

 the lateral portion of the ilio-femoral ligament. In circumduction^ which 

 is produced by combination of the movements of flexion, abduction, exten- 

 sion, and adduction, different parts of the capsular ligament are tightened 

 at different stages of the movement. 



The flexor nmscles of the hip joint are chiefly (i) the ilio-psoas, (2) 

 the rectus femoris, (3) the pectineus, (4) the adductors longus and brevis 

 and the pubic fibres of the adductor magnus ; the extensors are (i) the 

 glutaeus maximus, (2) the hamstrings, (3) the ischial fibres of the adductor 

 magnus, (4) the posterior fibres of the glutaeus medius, (5) the posterior 

 fibres of the glutaeus minimus; the adductor muscles are (i) the three 

 adductors, (2) the gracilis, (3) the pectineus, (4) the obturator externus, 

 (5) the lowest fibres of the glutaeus maximus, (6) the quadratus femoris ; 

 the abductors are (i) the upper part of the glutaeus maximus, (2) the 

 tensor fasciae latse, (3) the glutoeus medius, (4) the glutoeus minimus. 



The medial rotators are (i) the ilio-psoas, (2) the anterior part of the 

 glutaeus medius, (3) the anterior part of the glutaeus minimus, (4) the tensor 

 fasciae latse ; the lateral rotators are (i) the two obturator muscles, (2) 

 the gemelli, (3) the piriformis, (4) the quadratus femoris, (5) the three 

 adductors, (6) the pectineus, (7) the inferior fibres of the glutseus maximus, 

 (8) the ilio-psoas. 



It must be noted that the obturator muscles, the piriformis, and the 

 gemelli, which act as lateral rotators when the body is erect, become 

 abductors when the joint is flexed, and that the ilio-psoas is a flexor 

 of the hip joint and a medial rotator of the thigh until flexion is almost 

 complete, then it becomes a lateral rotator. 



Dissection. The hip joint should now be opened. Make 

 one incision along the upper border and another along the medial 

 border of the ilio-femoral ligament in order to isolate that band 

 from the rest of the capsule, then remove all other parts of the 

 capsule. The object of this dissection is to enable the dissector 

 to appreciate the great strength of the ilio-femoral ligament. 

 It is fully a quarter of an inch thick, and a strain varying from 

 250 Ibs. to 750 Ibs. is required for its rupture (Bigelow). It is 

 very rarely torn asunder in dislocations, and consequently the 

 surgeon is enabled in most cases to reduce the displacement by 

 manipulation. The ilio-femoral ligament may now be removed. 



Labrum Glenoidale (O.T. Cotyloid Ligament). The labrum 

 glenoidale is a firm fibro-cartilaginous ring, which is fixed to the 

 brim or margin of the acetabulum ; it bridges across the notch, 

 in the lower margin of the acetabulum, and thus completes 

 the circumference of the cavity, deepens it, and at the same 

 time narrows its mouth to a slight extent. The labrum 

 glenoidale fits closely upon the head of the femur, and, acting 

 like a sucker, exercises an important influence in retaining it in 

 place. Both surfaces of the labrum are covered with synovial 

 membrane ; its free margin is thin, but it is much thicker at 

 its attachment to the acetabular brim. 



