302 THE INFERIOR EXTREMITY 



Dissection. The glutaeus medius must now be reflected. 

 Keep the tensor fasciae pulled well forward. Insert the fingers 

 between the posterior borders of the glutaeus medius and minimus, 

 and separate the muscles, from behind forwards, to their anterior 

 margins, which were exposed and defined in the dissection of the 

 anterior part of the thigh (see p. 249). Then divide the medius 

 two inches above the trochanter major. Turn the lower part 

 towards the trochanter, into which it is inserted, and the upper 

 part towards its origin from the ilium. As the lower part of 

 the muscle is reflected to its insertion into the oblique line on 

 the lateral surface of the trochanter major, a small bursa will 

 be displayed between the muscle and the upper and anterior 

 part of the lateral surface of the trochanter. When the upper 

 part of the muscle is raised, towards its origin, the branches of 

 the superior gluteal vessels and the superior gluteal nerve, which 

 lie between the glutseus medius and minimus, will be exposed ; 

 they must be carefully cleaned and preserved, except the smaller 

 twigs which enter the deep surface of the glutaeus medius which 

 may be cut if they interfere with the reflection of the muscle. 

 As the branches of the artery and nerve are followed the super- 

 ficial surface of the glutaeus minimus must be cleaned. 



Nervus Glutaeus Superior. After emerging from the 

 pelvis, through the greater sciatic foramen, the superior 

 gluteal nerve turns forward, between the glutseus medius and 

 minimus, and immediately divides into an upper and a lower 

 branch. The upper branch follows the upper border of the 

 glutseus minimus and it gives branches to the glutseus medius. 

 The lower branch of the nerve crosses the middle of the 

 glutseus minimus with the lower branch of the superior 

 gluteal artery. It supplies branches to both the glutseus 

 medius and minimus, then passes between the anterior 

 borders of those two muscles and ends in the tensor fascise 

 latse. 



Arteria Glutaea Superior. The superior gluteal artery is 

 a large vessel which springs from the hypogastric artery and 

 escapes from the pelvis, through the upper part of the great 

 sciatic foramen, above the level of the piriformis. 



Immediately after its exit, it divides into a superficial and 

 a deep division. The superficial division has been already 

 seen during the reflection of the glutseus maximus. Its 

 branches are distributed to the deep surface of that muscle. 



The deep division bifurcates, close to its origin, into a 

 superior and an inferior branch, which run forwards between 

 the glutseus medius and minimus. The superior branch 

 follows accurately the anterior gluteal line on the dorsum ilii, 

 and, at the anterior superior spine, terminates by anastomos- 

 ing with the superficial and deep circumflex iliac arteries, 



