THE ABDOMEN 645 



downwards to the front of the thigh, but takes an upward 

 course. 



The fascia of Scarpa represents the tunica abdominalis of quadrupeds, which 

 is composed almost entirely of elastic tissue, and serves as an important 

 adjunct to the abdominal parietes. 



The deep fascia resembles that in other parts of the body in 

 being membranous. Laterally, where the external oblique is 

 fleshy, this fascia is well marked, but, as it approaches the confines 

 of the aponeurosis of that muscle, it becomes very delicate, and 

 ultimately disappears. Over the external oblique aponeurosis, 

 therefore, there is really no deep fascia properly so called, so that 

 the deep layer of the superficial fascia or fascia of Scarpa lies 

 directly upon the external oblique aponeurosis, to which it is loosely 

 connected by areolar tissue. 



Cutaneous Nerves. — The anterior cutaneous nerves are the 

 terminal branches of the lower five intercostal nerves and of the 

 anterior primary division of the twelfth thoracic nerve (subcostal 

 nerve). Having emerged through the anterior wall of the' sheath 

 of the rectus abdominis in a straggling manner, they give a few 

 twigs inwards, and then turn outwards to supply the anterior 

 abdominal integument, in which they communicate with the anterior 

 branches of the lateral cutaneous nerves. 



The hypogastric branch of ilio-hypogastric nerve pierces the 

 external oblique aponeurosis about i inch above the external 

 abdominal ring, and is distributed to the integument of the supra- 

 pubic region. It is serially continuous with the anterior cutaneous 

 nerves. 



The skin below the ensiform process is supplied by the seventh thoracic 

 nerve ; that on a level with the umbilicus by the tenth thoracic ; and that 

 over the lower half of the infra-umbilical region by the twelfth thoracic, and 

 the iUo-hypogastric. 



The lateral cutaneous nerves are branches of the lower fi.ve 



intercostal nerves. Having emerged between the serrations of the 

 external oblique muscle in the mid-axillary line, each divides into 

 an anterior and a posterior branch. The posterior branch turns 

 backwards to supply the integument over the lower part of the 

 back. The anterior branch passes forwards to supply the anterior 

 abdominal integument, in which it communicates wdth an anterior 

 cutaneous nerve. 



Cutaneous Arteries. — The superior or superficial external pudic artery arises 

 from the common femoral about J inch below Poupart's Ugament, after 

 which it pierces the crural sheath and cribriform fascia. Having emerged 

 through the saphenous opening, it passes inwards and upwards over the 

 spermatic cord, or round hgament of the uterus, according to the sex, to 

 be distributed to the integument of the suprapubic region, the adjacent 

 portion of the scrotum in the male and the labium majus in the female, and 

 the dorsum of the penis by a branch which extends as far as the prepuce, 

 lying external to the dorsalis penis artery. The vessel in its course gives 

 branches to the pubic glands, the deep femoral glands, and the coverings 

 of the spermatic cord, or of the round Ugament of the uterus. It anasto- 



