466 The Hip- Joint 



The capsule is attached beyond the border of the acetabulum. In 

 front it is extremely thick and descends to the intertrochanteric line, 

 but behind, where it is thin and membranous, it does not reach to 

 within a finger's breadth of the line. The anterior part is strengthened 

 by the ilio-femoral, or Bigelow's ' ligament, which descends like an 

 inverted Y from the anterior inferior iliac spine to the upper and lower 

 ends of the anterior intertrochanteric line. Fibres are reflected from 

 the lower end of the capsule up around the neck, these fibres strengthen 

 the periosteum ; thus, sometimes it happens that the neck is cracked 

 across without displacement occurring, the fragments being closely held 

 together by the thick periosteal covering. 



There is often a perforation in the front of the capsule, between 

 the branches of the Y ligament, by which the synovial membrane of 

 the joint communicates with the bursa beneath the psoas. Around 

 the border of the acetabulum, just inside the capsule, is the fibro- 

 cartilaginous cotyloid ligament, which acts as a ' sucker ' around the 

 head of the femur which it tightly embraces, securing its position 

 by atmospheric pressure. It stretches across the cotyloid notch at 

 the lower part of the acetabulum under the name of the transverse 

 ligament, vessels and nerves entering the joint beneath it. 



A synovial membrane lines the capsule and covers the neck of the 

 femur, but its continuity cannot be traced over the opposed articular 

 surfaces except in early fcetal life, as, under the influence of pressure, 

 it becomes absorbed. 



The ligamentum feres is a hollow fibrous pyramid, which passes 

 between the margin of a depression at the bottom of the acetabulum 

 and the pit below and behind the centre of the head of the femur. It 

 is surrounded by synovial membrane. It is not an important struc- 

 ture ; sometimes it is represented by a mere shred. It is, of course, 

 ruptured in dislocation. Possibly its chief function is to act as a 

 cushion. 



Relations of the hip- joint. In front art the iliacus and psoas, 

 the pectineus, the straight head of the rectus femoris and some of the 

 gluteus minimus. Behind are the pyriformis, gemelli and obturator 

 internus, obturator externus, and quadratus femoris. Above are the 

 reflected head of the rectus and the gluteus minimus, and below are 

 the obturator externus and the outer border of the pectineus. 



The anterior crural nerve and the common femoral vessels are 

 separated from the front of the capsule by the iliacus, psoas, and 

 pectineus ; and the sciatic vessels and nerves are separated from the 

 posterior aspect by the pyriformis, the gemelli and the obturator in- 

 ternus, and the quadratus femoris. 



Supplies Arteries come from the gluteal (above), the sciatic 

 (behind), the obturator and internal circumflex (below). Nerves enter 

 from the sacral plexus (. to quadratus), the great sciatic, obturator, 

 accessory obturator and anterior crural (. to rectus). 



