112 



DISSECTION OF THE BUTTOCK. 



and perfo- 

 rating 

 cutaneous 

 branch. 



Clean 

 gluteus 

 maximus ; 



mode of 

 proceeding. 



Fascia of the 

 buttock. 



Glutens 

 maximus : 



origin ; 



insertion ; 



relations of 

 the surfaces, 



and borders : 



part of the buttock ; the remaining branches ( 2 ) descend to the 

 thigh, and will be afterwards noticed on it (p. 130). 



The PERFORATING CUTANEOUS NERVE of the sacral plexus ( 4 ) 

 turns round the edge of the glutens maximus near the coccyx, and 

 supplies the skin of the adjacent part of the buttock : this nerve 

 has been exposed in the dissection of the perineum. 



Dissection. The thin and unimportant deep fascia of this region 

 may be disregarded, in order that the great gluteal muscle, which 

 is one of the most difficult in the body to clean, may be well dis- 

 played. To lay bare the muscle, let the student turn aside the 

 cutaneous nerves, and adduct and rotate inwards the limb to make 

 tense the muscular fibres. HaAdng cut through the fat and fascia 

 from the origin to the insertion, let him carry the scalpel along one 

 bundle of fibres at a time in the direction of a line from the sacrum 

 to the femur, until all the coarse fasciculi are cleaned. If the 

 student has a right limb, it will be more convenient to begin the 

 dissection at the upper border ; but if a left limb, at the lower 

 margin of the muscle. 



The fascia of the buttock is a prolongation of that enveloping the 

 thigh, and is fixed to the crest of the ilium, and to the sacrum and 

 coccyx. It is much thicker in front of, than on the glutens 

 maximus, and gives attachment superiorly to the glutens medius, 

 which it covers ; in this place, indeed, the student often has some 

 difficulty in defining the edge of the greater glutens, since at the 

 edge of the muscle the fascia splits to encase it. 



The GLUTEUS MAXIMUS (fig. 46, A) is the most superficial 

 muscle of the buttock, and reaches from the pelvis to the upper 

 part of the femur. Its origin from the pelvis is fleshy, and is 

 connected with bone and with aponeurosis : Thus, the muscle is 

 attached, from above down, to the posterior fourth of the iliac 

 crest, and to a special impression on the hip-bone above the superior 

 curved line (fig. 47) ; next, to the aponeurosis of the erector spinue 

 muscle ; then to the back of the fourth and fifth pieces of the 

 sacrum, and the back of the coccyx ; and lastly, to the back of the 

 whole length of the great sacro-sciatic ligament. From this 

 extensive origin the fibres are directed downwards and outwards to 

 their insertion : The whole of the upper half of the muscle, and a 

 few superficial fibres of the lower half are inserted into the strong 

 fascia lata (ilio-tibial band) of the outer side of the thigh ; and the 

 remainder are fixed into the rough line (gluteal ridge) leading from 

 the linea aspera to the great trochanter of the femur (fig. 61, 

 p. 158). 



The glutens forms the prominence of the buttock, and resembles 

 the deltoid muscle of the arm in its situation and in the coarse- 

 ness of its texture. Its cutaneous surface is covered by the common 

 integuments and the investing fascia of the limb, and by the superficial 

 nerves and vessels. The structures in contact with the under surface 

 will be seen when the muscle is cut through. The upper border 

 overlies the glutens medius. The lower edge, which is longer 

 and thicker than the upper, in its inner part bounds posteriorly 



