37 



anteriorly and enters the precural group of muscles between the rectus 

 femoris and vastus internus. It supplies branches to the iliacus and the 

 quadriceps femoris muscles. 



Exposure of the gluteal vessels and nerves. 



Remove the skin from the gluteal and femoral regions. Dissect be- 

 tween the biceps femoris and the adjoining muscles, viz., the gluteus superfi- 

 cialis and vastus extemus, anteriorly, and the semitendinosus, posteriorly. 

 Also dissect between the semitendinosus and the semimembranosus. Tran- 

 sect the semitendinosus opposite the ischial tuberosity and draw aside the 

 proximal portion just enough to expose the nerve and blood-vessels that 

 enter it immediately dorsal to the ischial tuberosity (PI. IV, 25). Transect 

 the biceps femoris at the level of the external small trochenter and also at the 

 level of the nerve, just exposed, to the semitendinosus, i.e. immediately 

 dorsal to the ischial tuberosity. In this latter transection one of the large 

 nerve branches to the biceps femoris will probably be cut; the other large 

 nerve branch to this muscle lies more deeply and may be seen readily if the 

 proximal portion of the muscle be drawn aside. Trace both of these 

 large branches peripherally for some distance. Upon drawing aside the 

 proximal portion of the biceps femoris it will be seen that the two or three 

 large branches just mentioned (and the A. and V. glutea posterior) emerge 

 from beneath the gluteus medius and are distributed to the biceps femoris 

 and also one small branch to the posterior border of the gluteus super- 

 ficial is (PI. IV, 23). These large nerve branches cannot be traced at present 

 to their place of origin from one of the posterior gluteal nerves. Now 

 dissect between the tensor fasciae latae and the gluteus superficialis taking 

 care not to cut the nerve or blood-vessels that emerge from beneath the 

 anterior edge of the gluteus superficialis near its middle, and enter the 

 adjoining borders of the tensor fasciae latae and the gluteus superficialis 

 (PL IV, 22). Transect the gluteus superficialis a little proximal to the 

 nerve just exposed, turn it aside somewhat, and note the small nerves and 

 blood-vessels supplied to its anterior edge. The gluteus medius should 

 now be transected a little proximal to the two above mentioned nerves 

 that emerge from beneath the respective anterior and posterior borders 

 of the muscle, i.e. the nerve to the tensor fasciae latae and the nerve to 

 the biceps femoris (PL IV, 22, 23). The deep face of the gluteus medius is 

 indicated by these two nerves and they should be kept in view while transect- 

 ing the muscle; this maybe done if while transecting it, the proximal portion 

 of the muscle be freed largely from its attachment to the iliac fossa and the 

 sacrum and turned back. Note the vein and artery — ^A. iliolumbalis — 

 that cross the external border of the ilium from 5 to 8 cm. ventral to the 



