274 ANATOMY OF THE RABBIT 



2. Aluscles arising from the pelvic girdle and sacrum and inserted 

 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 (p. 278), which must be examined and divided. To 

 begin the dissection, identify the sciatic vein (p. 280) on the 

 lateral surface of the thigh and cut the fascia along the proximal 

 part of its course, where it runs in a nearly transverse direction. 

 This procedure will free the first portion of the biceps in front from 

 the superficial head of the semimembranosus behind. A continu- 

 ation of the same incision distad and towards the front of the thigh 

 along a line which is usually clearly visible, and which delimits the 

 first portion of the biceps from the second, will separate these two 

 portions. Now cut along the tendinous line which may be observed 

 joining the tip of the great trochanter with the sacrum and carry 

 the incision distad along the intermuscular septum of the lateral 

 surface of the thigh to the knee. The first head of the biceps, 

 having been freed both in front and behind by these manipulations, 

 should now be raised slightly by working the handle of the scalpel 

 under its distal portion. Divide the muscle, starting at its posterior 

 margin and being careful not to injure the slender tensor fasciae 

 cruris muscle and the branches of the sciatic nerve which lie beneath 

 it. Reflecting the proximal end will expose the short muscles of 

 the thigh. 



Dissect on the lateral surface posteriorly. 



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

 joined by an aponeurosis. First portion: 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 of the muscle should be divided. The 

 sciatic nerve and artery are then exposed. 



