THE BUTTOCKS 



11.^1 



maximus, especially behind and below, and in less degree to the other two ^dutei 

 in front. Under the lower edge of the gluteus maximus the edge of the great sacro- 

 sciatic ligament can be felt on deep ])ressure'. 



Nerves and vessels. — The following superficial nerves can Ije marked in 

 over the buttock (fig. 770). Behind the gnat troclianter, branclies of the external 

 cutaneous. Coming down over the crest, the lateral cutaneous l>ranch of the last 

 dorsal (aljout in a line with the great trochanter), and ])eliind this the lateral 

 branch of the ilio-liypogastric. Two or three offsets of the posterior primary 

 branches of the lumbar nerves cross the hinder part of the iliac crest at the outer 

 margin of the erector spinte. Two or three twigs from the posterior divisions of 

 the sacral nerves pierce the gluteus maximus close to the coccyx and sacrum, and 

 ramify outwards. Finally, over the lower border of the gluteus maximus turn 

 upwards branches of the small sciatic and inferior jtudendal and fourth sacral 

 nerves. 



Great sciatic nerve (figs. 748, 749). — The point of emergence below the 



Fig. 747.— Sectiox through the Hip and Gliteal Region. (Oue-third.) 



SartoriuB 



Refieeted tendon 



rectus 

 Psoas and iliacus 



and bursa ^s ^^ \ 

 AyTERIOR , ^-^^ y-] 

 CRURAL SERVE ""---.[^n/' 

 Cnmmon feinonil ~^^ // Ij i» 

 arleri/ "/^/'fr 



Cumiiton femoral rein ^^ '/ \ ry/ 



Profimria vessrls ■^^%. 'f *^ 



Semi-membranoBUB •^.^~^- 

 Adductor brevis z£.^/-\ 

 Semi-tendlnosuB ■'-- 

 Obturator exteruus -- 

 Adductor longus -'■ 

 Adductor magnus 



Gluteus maximus 

 Gluteus mediuB 



- Gluteus minimus 



Pyrlformls 

 GREA T SCIA TIC 



SERVE and sciati 



res.sf'ts 

 Obtura'or internus 

 Gemelli 



Biceps 

 Quadratus femoris 



gluteus maximus and the track of this nerve will be given by a line drawn from a 

 spot a little internal to the middle of the space between the great trochanter and the 

 tuber ischii to the lower part of the back of the thigh. The inferior pudendal 

 perforates the deep fascia about an inch (25 nun.) in front of the tuber ischii, antl 

 turns forwards to su})i)ly the genitals. 



Gluteal artery. — If a line be drawn from the posterior superior si)ine to the 

 apex of the great trochanter, the limb being slightly flexed and rotated inwards, 

 the point of emergence of the artery from the upper part of the great sacro-sciatic 

 notch will correspond with the junction of the upper and middle third of this line 

 (fig. 746) (MacCormac). The gluteal nerve emerges immediately below the 

 artery, and sends branches with the deeper portion. 



Sciatic and pudic arteries. — The limV> l>eing rotated inwards, a line is drawn 

 from the ])()st<,'rior superior sjiinc to the outer ])art of the tuber ischii. The ]»oint 

 of exit of the above arteries will correspond to the junction of the middle and 

 lower thirds of this line (MacCormac). 



