232 INFERIOR EXTREMITY 



ternus. Its terminal branches ramify in the neighbourhood of 

 the fossa trochanterica, where they anastomose with twigs from 

 the inferior and superior and glutaeal arteries. The transverse 

 branch passes posteriorly, between the quadratus femoris and 

 the adductor magnus, and enters the hamstring muscles. It 

 anastomoses with the terminal twig of the middle division of 

 the lateral circumflex artery, which in a well-injected subject 

 will be noticed appearing from amidst the fibres of the proximal 

 part of the vastus lateralis. An arterial circle is thus com- 

 pleted around the proximal part of the femur which com- 

 municates proximally with the inferior glutaeal artery and 

 distally with the first perforating artery. This series of in- 

 osculations is sometimes spoken of as the crucial anastomosis 

 of the thigh. 



Dissection. The dissector has now examined all the structures in the 

 gluteal region which lie distal to the level of the piriformis. He should, 

 in the next place, turn his attention to that portion of the dissection which 

 lies proximal to the level of that muscle. Here are found a number of parts 

 in close relation to the dorsum ilii. These are the glutaeus medius, the 

 glutoeus minimus, and the tensor fasciae latae, together with the blood-vessel 

 and nerve which supply them, viz. the superior glutaeal artery and the 

 superior glutaeal nerve. 



The hinder part of the glutaeus medius muscle is covered by the 

 glutaeus maximus. Its anterior border is overlapped by the tensor fasciae 

 latae, and the intermediate area is invested by the dense aponeurotic layer 

 already referred to. This fascia must be removed in order that a satis- 

 factory view of the muscle may be obtained. It will then become evident 

 that numerous fleshy fibres arise from the deep surface of the fascia. 



M. Glutseus Medius. The glutaeus medius arises from 

 that part of the dorsum ilii which is bounded above by the 

 posterior curved line and the anterior four-fifths of the crest of 

 the ilium, and below by the anterior curved line (Fig. 84, p. 

 222); it also derives fibres from the strong fascia which 

 covers it. The fibres converge to form a flattened band, 

 partly fleshy and partly tendinous, which is inserted into an 

 oblique line on the lateral aspect of the greater trochanter 

 of the femur, and into the surface immediately above it. 

 The glutaeus medius muscle is supplied by the superior glutceal 

 nerve. 



Dissection. The glutaeus medius must now be reflected. This dis- 

 section is complicated by the fact that in its proximal and anterior part 

 the glutaeus medius is partially blended with the subjacent glutseus mini- 

 mus and the tensor fasciae latae. Begin by rotating the limb medially. 

 Then seizing the glutseus maximus with the left hand, pull it laterally, and 

 divide the glistening aponeurosis into which it is inserted for two or three 



