SUPERFICIAL PARTS, HOW SHOWN. 405 



be connected along the side of the chest and the belly. The piece of skin 

 thus marked out is to be raised towards the middle line, but is not to be 

 taken away; and the cutaneous vessels and nerves are to be sought in the 

 fat at the side and middle line of the abdomen. 



Along the side of the abdomen look for the lateral cutaneous nerves, 

 five or six in number, which issue in a line with the corresponding nerves 

 of the thorax. At first they lie beneath the fat, and divide into two : one 

 offset is to be traced forwards, and the other backwards, with small cuta- 

 neous arteries. On the iliac crest, near the front, is a large branch from 

 the last dorsal nerve ; and usually farther back on the crest, and deeper, 

 is a small branch of the iliohypogastric nerve. Near the middle line the 

 small anterior cutaneous nerves will be recognized with small arteries; 

 these are uncertain in number and size, and are to followed outwards in 

 the integuments. 



The piece of skin covering the lower part of the abdomen or the groin 

 is next to be thrown downwards, on both sides, by an incision along the 

 middle line to the root of the penis. After its reflection th cutaneous 

 vessels and nerves are to be dissected on the right side, and the superfi- 

 cial fascia on the left. 



To make the necessary dissection on the right side, all the fascia super- 

 ficial to the vessels is to be raised in the same manner as the piece of skin. 

 The vessels which will then appear are the superficial pudic internally, 

 the superficial epigastric in the centre, and an offset of the superficial 

 circumflex iliac artery externally. Some inguinal glands lie along the 

 line of the reflected fascia. Two cutaneous nerves are to be sought : one, 

 the ilio-inguinal, comes through the abdominal ring, and descends to the 

 thigh and scrotum ; the other, ilio-hypogastric, appears in the superficial 

 fascia above, and rather outside the abdominal ring. 



In the examination of the fatty layer on the left side two strata are to 

 be made out, one over and one beneath the vessels. The layer that is 

 superficial to the vessels is to be reflected by means of a transverse cut 

 from the front of the iliac crest, about two inches above Poupart's liga- 

 ment ; and by a vertical one near the middle line to the pubes. The sub- 

 jacent vessels mark the depth of this layer ; and when these are reached, 

 a flap of the fascia, like that of the skin, is to be thrown towards the 

 thigh. To define the thinner under stratum, cut it across in the same 

 manner as the other layer, and detach it with the vessels from the tendon 

 of the external oblique muscle. This stratum, like the preceding, is to 

 be traced around the cord to the scrotum ; and as the student follows it 

 downwards, he will find it connected with Poupart's ligament, and blended 

 with the fascia lata close below that structure. 



The subcutaneous fat, or the superficial fascia, is a single layer over 

 the greater part of the abdomen ; but in the groin it is divided into a sub- 

 cutaneous and a deeper stratum by the vessels and the glands. 



The subcutaneous layer contains fat, and varies therefore in appear- 

 ance and thickness in different bodies ; for it is sometimes divisible into 

 strata, whilst at others it is very thin, and somewhat membranous near 

 the thigh. It is continuous with the fatty covering of the thigh and ab- 

 domen ; and when traced to the limb, it is separated from Poupart's liga- 

 ment beneath by the superficial vessels and glands. Internally it is con- 

 tinued to the penis and scrotum, where it changes its adipose tissue for 

 involuntary muscular fibre ; and after investing the testicle, it is prolongel 

 to the perina?um. 



