250 ANATOMY OP THE LOWER E.XTREMITY. 



The lesser sacro-ischiatic ligament arises from the side 

 of the sacrum and coccyx, and is inserted into the spine o1 

 the ischium. These two ligaments convert the space be- 

 tween the sacrum and os innominatum into two apertures, 

 called the greater and lesser sacro-ischiatic foramina, 

 through which issue the nerves, arteries, and muscles from 

 the interior of the pelvis. 



The union of the pubic bones in front is called the sym- 

 physis pubes. 



The anterior pubic ligament consists of horizontal and 

 oblique fibres, interlacing in front of the symphysis. The 

 periosteum constitutes the posterior pubic ligament. 



The superior pubic ligament covers the surface of the 

 bones superiorly, and blends with the tendinous insertions 

 of the abdominal muscles. 



The sub-pubic ligament is a fibrous arch attached to the 

 bones of the pubes inferiorly, and losing itself at each side 

 on the rami of the ischia. 



The inter-articular fibro-cartilage, seen on opening the 

 symphysis, is composed of concentric Ia3 r ers of fibres firmly 

 attached to the opposed surfaces of the bones, and project- 

 ing a little beyond their borders. At the posterior part, a 

 cavity, containing a fluid like the synovial, and of variable 

 size, will be found separating the cartilage into two lateral 

 halves ; this cavity is said to increase in size during preg- 

 nancy. 



The obturator ligament, or membrane, is a tendino-fibrous 

 expansion, which stretches across the obturator foramen, 

 and closes it in its entire extent, except at the upper part, 

 where the obturator artery and nerve pass out of the pelvis. 



The COXO-FEMORAL ARTICULATION, or HIP-JOINT, in 

 which the head of the femur is received into the cot}"loid 

 cavity of the os innominatum, is maintained by a capsular 

 and an inter-articular ligament. 



The capsular ligament extends from the circumference of 

 the acetabulum to the anterior inter-trochanteric line of the 

 femur in front and to the neck of the bone posteriorly. It 

 is strengthened anteriorly by a band of fibres, called the 

 ilio-femoral ligament, which passes from the anterior infe- 

 rior spinous process of the ilium to the inter-trochanteric 

 line. The anterior portion of the capsular ligament is of 



