1H 



DISSECTION OB 1 THE BUTTOCK. 



clean parts 

 beneath, 



remove 

 origin, 



and dissect 

 out sacral 

 nerves. 



Parts 



covered by 

 gluteus at 

 its origin 



and inser- 

 tion ; 



and by the 

 intervening 

 piece of the 

 muscle. 



be ascertained by the fascia and some vessels beneath it. When 

 this intermuscular layer is arrived at, the outer piece of the gluteus 

 may be at once thrown towards its insertion ; but the inner piece 

 is to be carefully raised, and the branches of the inferior gluteal 

 nerve, and of the gluteal and sciatic arteries entering its deep 

 surface, are to be cleaned. 



The loose fat is then to be taken away from the hollow between 

 the pelvis and the trochanter, without injuring the vessels and 

 nerves ; and the several muscles are to be cleaned, the fibres of 

 each being made tense at the time of its dissection by rotating the 

 femur. The vessels, nerves, and muscles, which are to be defined 

 may be ascertained by referring to the enumeration below of the 

 parts beneath the gluteus. In removing the areolar tissue from 

 the ischial tuberosity and from the great trochanter, a bursa over 

 each prominence of bone may be observed. 



Lastly, the fibres of the muscle are to be detached at their origin ; 

 and the inner piece may be removed entirely by cutting through 

 the vessels and nerves that enter it. In doing this the sacral nerves 

 are to be dissected out of the fleshy fibres, and to be followed to the 

 surface of the great sacro-sciatic ligament, where they will be 

 afterwards seen. 



Parts beneath the gluteus (fig. 48). At its origin the gluteus 

 maximus rests on the pelvis, and conceals part of the ilium, sacrum 

 arid coccyx, also the ischial tuberosity with the origin of the ham- 

 string muscles (L) and the great sacro-sciatic ligament (K). At its 

 insertion it covers the upper end of the femur, with the great 

 trochanter, and the origin of the vastus extern us (i). Between 

 the muscle and the trochanter is a large, loose synovial 

 membrane ; between it and the vastus externus is another 

 synovial sac ; and occasionally there is a third over the ischial 

 tuberosity. 



In the hollow between the pelvis and the femur the muscle 

 conceals, from above downwards, the undermentioned parts 

 (fig. 48) : First, a portion of the gluteus medius (A) ; and below 

 it the pyriformis (B), with the superficial branch of the gluteal 

 vessels between the two. Coming from beneath the pyriformis are 

 the inferior gluteal nerve supplying the gluteus maximus, and the 

 large ( 6 ) and small sciatic nerves, with the sciatic vessels, which 

 descend to the thigh between the great trochanter and the ischial 

 tuberosity ; and internal to the sciatic are the pudic vessels and 

 nerve, and the nerve to the obturator internus muscle, which 

 are directed inwards through the small sacro-sciatic foramen. 

 Still lower down is the tendon of the obturator internus muscle (D) 

 with a fleshy fasciculus the gemellus (c and E) above and below 

 it. Next comes the quadratus femoris muscle (G) with the upper 

 part of the adductor magnus (H) ; at the upper border of the 

 quadratus, and deep to it, is the tendon of the obturator externus ; 

 and at the lower border, between it and the adductor, issues one of 

 the terminal branches of the internal circumflex artery with its 

 veins. 



