DISSECTION OF THE LOWER EXTREMITY 123 



(bursa subcutanea trochanterica). Draw the shortest possible 

 line on the surface from the tuber ischiadicum to the spina 

 iliaca anterior superior and note the relation which the upper 

 extremity of the trochanter major bears to this line. Palpate 

 the structures forming the boundaries of the popliteal fossa. 

 Note the mobility of the skin over the malleoli (bursa subcutanea 

 malleoli later alls et medialis). Feel the tendons in the retro- 

 malleolar fossa. Palpate the various bony prominences that can 

 be felt about the ankle and foot, and identify each by comparison 

 with the skeleton. 



GLUTEAL EEGION (REGIO GLUTAEA). 



Make the following incisions (see Fig. 3) : 



(1) From the spina iliaca posterior superior along the crista iliaca as 



far forward as possible. 



(2) From the posterior extremity of this incision obliquely downward and 



medialward to the middle line of the sacral region, then vertically 

 downward to the tip of the coccyx. 



(3) From the tip of the coccyx downward and lateralward over the back 



of the thigh, intersecting the sulcus glutaeus at its middle point, 

 and terminating a little below the upper third of the thigh. 



The flap of skin thus formed should now be reflected lateralward, 

 leaving intact the fat immediately beneath. There is now ex- 

 posed to view- 

 Superficial Fascia. 



Note the abundance of fat. How does the amount of fat 

 contained compare in the male and female? Observe its tough, 

 fibrous character over the tuber ischiadicum. This fascia should 

 now be removed by blunt dissection. Find the following : 



Nerves. (Fig. 47.) 



(a) Middle nerves of buttock (Nn. clunium medii). These pierce the 

 glutaeus maximus and the deep fascia in a line passing from the 

 spina iliaca posterior superior to the tip of the coccyx. 



(&) Superior nerves of buttock (Nn. clunium superior es], crossing the 

 crista iliaca at a point corresponding to the lateral limit of the 

 attachment of the musculus sacrospinalis to the os ilium. 



(c) Lateral cutaneous ramus of iliohypogastric nerve (ramus cutaneus 



lateralis nervi iliohypogastrici). It generally crosses the iliac 

 crest opposite a tubercle projecting from its outer lip, about two 

 and one-half inches dorsal to the spina iliaca anterior superior. 



(d) Lateral cutaneous ramus of last thoracic nerve (ramus cutaneus 



lateralis N. thoracalis 7.) (0. T. last dorsal nerve). This nerve 

 crosses the iliac crest a short distance anterior to the preceding. 



