450 PRACTICAL ANATOMY. 







the intercostal nerves. One of these, from the second 

 intercostal, communicates with the lesser internal cuta- 

 neous. It is called the intercosto-humeral nerve, and is 

 ultimately distributed to the integument near the elbow. 

 The lymphatic glands of the axilla communicate with the 

 cervical. They are of from ten to fifty in number and 

 of variable size. 



THE PERINEUM. 



The male perineum is the diamond-shaped space 

 limited in front by the scrotum, behind by the tip of the 

 coccyx, laterally by the tuberosities of the ischia, the 

 rami of the ischia and pubes, and the greater and lesser 

 sacro-sciatic ligaments. A line drawn transversely 

 through the tuberosities of the ischia subdivides this 

 region into an anterior, the perineum proper, and a pos- 

 terior, the ischio-rectal region. The skin of the peri- 

 neum is pigmented, tightly adherent, thrown into numer- 

 ous fine, transverse rugae, and presents a median raphe, 

 continuous with the raphe of the scrotum. It is covered 

 by scattered, short, stiff hairs. Over the ischio-rectal 

 region the skin is less firmly attached to the subcutaneous 

 structures ; the pigmentation is strongly marked about 

 the anus, which is situated in the median line midway 

 between the perineum and the coccyx. It presents 

 numerous folds radiating from the anal aperture. Upon 

 removing the skin of the perineum the superficial fascia 

 is exposed. This fascia consists of two layers, super- 

 ficial and deep. The superficial layer is continuous with 

 the outer layer of the superficial fascia of the abdomen, 

 thighs, and ischio-rectal region, and is loaded with fat. 

 The deep layer of the superficial fascia is continuous with 

 the deep layer of the superficial fascia of the abdomen. 

 In the perineum it is much thickened and firmly attached 



