258 INTERNAL FEMORAL REGION. 



This is named, from its situation, sub-crureus, and would seem to be 

 intended to support the synovial membrane. 



Relations. By its superficial surface with the external circumflex 

 vessels, the rectus, vastus internus and externus. By its deep surface 

 with the femur, the sub-crureus, and synovial membrane of the knee- 

 joint. 



Actions. The tensor vaginae femoris renders the fascia lata tense, 

 and slightly inverts the limb. The sartorius flexes the leg upon the 

 thigh, and, continuing to act, the thigh upon the pelvis, at the same 

 time carrying the leg across that of the opposite side, into the position 

 in which tailors sit; hence its name. Taking its fixed point from 

 below, it assists the extensor muscles in steadying the leg, for the sup- 

 port of the trunk. The other four muscles have been collectively 

 named quadriceps extensor, from their similarity of action. They 

 extend the leg upon the thigh, and obtain a great increase of power 

 by their attachment to the patella, which acts as a fulcrum. Taking 

 their fixed point from the tibia, they steady the femur upon the leg, 

 and the rectus, by being attached to the pelvis, serves to balance the 

 trunk upon the lower extremity. 



Internal Femoral Region. 



Iliacus internus, 

 Psoas magnus, 

 Pectineus, 

 Adductor longus, 

 Adductor brevis, 

 Adductor magnus, 

 Gracilis. 



Dissection. These muscles are exposed by the removal of the inner 

 flap of integument recommended in the dissection of the anterior 

 femoral region. The iliacus and psoas arising from within the abdo- 

 men can only be seen in their entire extent after the removal of the 

 viscera from that cavity. 



The ILIACUS INTERNUS is a flat radiated muscle. It arises from 

 the whole extent of the inner concave surface of the ilium ; and, after 

 joining with the tendon of the psoas, is inserted into the trochanter 

 minor of the femur. A few fibres of this muscle are derived from the 

 base of the sacrum, and others from the capsular ligament of the hip- 

 joint. 



Relations. By its anterior surface, within the pelvis, with the ex- 

 ternal cutaneous nerve, and with the iliac fascia, which separates the 

 muscle from the peritoneum, on the right from the caecum, and on the 

 left from the sigmoid flexure of the colon ; externally to the pelvis with 

 the fascia lata, rectus, and sartorius. By its posterior surface with the 

 iliac fossa, margin of the pelvis, and with the capsule of the hip-joint, 

 a synovial bursa of large size being interposed, which is sometimes 



