The Surgical Anatomy of Inguinal Hernia. 



Dissection (Fig. 446). For the dissection of the parts concerned in inguinal hernia, a male 

 subject, free from fat, should always be selected. The body should be placed in the supine posi- 

 tion, the abdomen and pelvis raised by means of blocks placed beneath them, and the lower ex- 

 tremities rotated outwards, so as to make the parts as tense as possible. If the abdominal walls 

 are flaccid, the cavity of the abdomen should be inflated by an aperture through the umbilicus. 

 An incision should be made along the middle line, from the umbilicus to the pubes, and con- 

 tinued along the front of the scrotum ; and a second incision, from the anterior superior spine 

 of the ilium to just below the umbilicus. These incisions should divide the integument; and the 

 triangular-shaped flap included between them should be.reflected downwards and outwards, when 

 the superficial fascia will be exposed. 



Inguinal Hernia is that form of protrusion which makes its way through the 

 abdomen in the inguinal region. 



The superficial fascia in this region consists of two layers, between which are 

 found the superficial vessels and nerves, and the inguinal lymphatic glands. 



The superficial layer is thick, areolar in texture, containing adipose tissue in 

 its meshes, the quantity of which varies in different subjects. Below, it passes 

 over Poupart's ligament, and is continuous with the outer layer of the superficial 

 fascia of the thigh. This fascia is continued as a tubular prolongation around 

 the outer surface of the cord and testis. In this situation, it changes its charac- 

 ter ; it becomes thin, destitute of adipose tissue, and of a pale reddish color, and 

 assists in forming the dartos. From the scrotum, it may be traced backwards 

 to be continuous with the superficial fascia of the perineum. This layer should 

 be removed, by dividing it across in the same direction as the external incisions, 

 and reflecting it downwards and outwards, when the following vessels and nerves 

 will be exposed : 



The superficial epigastric, superficial circumflex iliac, and external pudic ves- 

 sels ; the terminal filaments of the ilio-hypogastric and ilio-inguinal nerves; and 

 the upper chain of inguinal lymphatic gland. 



The superficial epigastric artery crosses Poupart's ligament, and ascends ob- 

 liquely towards the umbilicus, lying midway between the spine of the ilium 

 and the pubes. It supplies the integument, and anastomoses with the deep epi- 

 gastric. This vessel is a branch of the common femoral artery, and pierces the 

 fascia lata, below Poupart's ligament. Its accompanying vein empties itself 

 into the internal saphenous, after having pierced the cribriform fascia. 



The superficial circumflex iliac artery passes outwards towards the crest of the 

 ilium. 



The superficial external pudic artery passes transversely inwards across the 

 spermatic cord, and supplies the integument of the hypogastric region, and of 

 the penis and scrotum. This vessel is usually divided^ in the first incision made 

 in the operation for inguinal hernia, and occasionally requires the application 

 of a ligature. 



The veins accompanying these superficial vessels are usually much larger 

 than the arteries; they terminate in the internal saphenous vein. 



Lymphatic vessels are found, taking the same course as the bloodvessels ; they 

 return the lymph from the superficial structures in the lower part of the abdo- 

 men, the scrotum, penis, and external surface of the buttock, and terminate in 

 a small chain of lymphatic glands, three or four in number, which lie on a level 

 with Poupart's ligament. 



Nerves. The terminal branch of the ilio-inguinal nerve emerges at the ex- 

 ternal abdominal ring ; and the hypogastric branch of the ilio-hypogastric nerve 

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