The Posterior Limb. 219 



2. Muscles arising from the pelvic girdle and sacrum and in- 

 serted on the femur, for the most part at its proximal extremity. 



The muscles of this group enclose the proximal portion of the 

 femur on its lateral, posterior, and medial sides. They are partly 

 covered by the flexors of Group 3, namely, the biceps, sartorius, and 

 gracilis (pp. 222, 223), which must be divided. To begin the 

 dissection, see directions for removing the biceps (p. 223). The 

 position of the sciatic vein (p. 225) should be noted. 



Dissection on the lateral surface posteriorly. 



(a) The glutaeus maximus. Origin in two fleshy portions, 

 joined by an aponeurosis: 



First por don : Fascia covering the sacrum in its entire length. 



This portion is triangular in shape, and is covered posteriorly 



by the first head of the biceps. 



Second portion: Anteroventral border of the iliac wing, 



fused with the tensor fasciae latae and the first head of the 



rectus femoris ; also from the dorsal border and lumbar fascia 



through the aponeurosis mentioned above. 



Insertion: Third trochanter. The axis of the first portion 



is transverse, that of the second horizontal. 



Both portions o' the muscle should be divided. The sciatic nerve 

 and artery are then exposed. 



(b) The glutaeus medius. Anterior border of the wing of the 

 ilium and the iliac crest and fascia of the first two sacral 

 vertebrae. Insertion: Greater trochanter. Some of the 

 fibres pass around the medial surface of the tip of the greater 

 trochanter and are inserted in the lateral wall of the tro- 

 chanteric fossa. 



The muscle should be divided. 



(c) The glutaeus minimus. Origin: Entire lateral surface 

 of the body and wing of the ilium. Insertion: Greater 

 trochanter. 



■ Remove the entire muscle. The piriformis is irf. contact with its 

 • dorsal margin posteriorly. 



(d) The tensor fasciae latae. Origin: Anterior portion of the 

 ventral border of the wing of the ilium. Insertion: Broad 



