3 8 2 APPLIED ANATOMY. 



done by making the incision through the inner edge of the muscle. If the method 

 of Battles is resorted to, of dividing the outer edge of the sheath of the rectus longi- 

 tudinally and displacing the muscle inward, or of dividing the muscle itself longitudi- 

 nally, then not only are large branches of the deep epigastric arteries met but in 

 dividing the posterior layer of the sheath the nerves are divided. If the rectus is 

 divided transversely (as Kocher advises in operations on the gall-bladder) care must 

 be taken to avoid wounding the nerves ; he claims that the scar acts only as an 

 additional linea transversa and does not injure the functions of the muscle. Injury 

 to the nerves and rectus muscle both can be avoided by incising the sheath transversely 

 and then pulling the rectus to one side (Weir), or by dissecting up the sheaths of 

 both recti transversely and separating the muscles in the median line ( Pfannenstiel 

 and Stimson). 



Incisions through the transverse muscles if made in the same direction through 

 all three muscles are bound to cut some in a direction more or less transverse to their 

 fibres. The incision of McBurney for appendicitis avoids wounding the muscles. 

 He separated the external oblique in the direction of its fibres downward and inward, 

 crossing a line from the anterior superior spine to the umbilicus, 4 to 5 cm. ( i ^ to 

 2 in. ) to the inner side of the spine. The internal oblique and transversalis are then 

 separated in the direction of the fibres and drawn in the opposite direction. This 

 method is applicable where small openings suffice ; but when large incisions are essen- 

 tial, as in bad suppurating cases of appendicitis and in operations to expose the 

 kidney and ureter, it is customary with many to incise all the muscles in the line of 

 the fibres of the external oblique. Should nerves be encountered they are if possible 

 to be drawn aside. In this incision the internal oblique and transversalis are incised 

 nearly transversely, and bleeding from the deep circumflex iliac artery which runs 

 between them will be encountered. 



Edebohls exposes the kidney by incising alongside of the outer edge of the 

 erector spinse muscle. The latissimus dorsi is separated in the direction of its fibres, 

 the lumbar aponeurosis is incised and kidney exposed. A normal kidney can be 

 delivered through this incision, but not one much enlarged. When the kidney is 

 much enlarged the incision is to be prolonged anteriorly along the crest of the ilium 

 (see page 396). The relation of the pleura is to be borne in mind: it crosses the 

 twelfth rib about its middle to reach its lower edge posteriorly. Hence the upper end 

 of the incision should always be kept anterior to it (see section on Pleura). 



HERNIA. 



Abdominal herniae occur most often in the umbilical and inguinal regions. 

 Sometimes the recti muscles separate and a median protrusion results; or they may 

 occur at the site of a previous operation. 



Umbilical berniae are of three kinds, congenital, infantile, and acquired. 



Congenital umbilical hernia is due to a developmental defect. In the embryo 

 the umbilicus transmits ( i ) the vitelline duct, passing from the umbilical vesicle to 

 the small intestines; (2) two umbilical arteries, which inside the abdomen are called 

 hypogastric and pass to the internal iliacs through the superior vesicals; (3) one 

 umbilical vein passing to the liver through the round ligament; (4J the stalk of 

 the allantois, which, on entering the abdomen, is called the urachus, and passes 

 down to the bladder. At birth these structures, with a myxomatous tissue called 

 Wharton's jelly, are covered with amniotic tissues and form the umbilical cord. 



If development is interfered with, a cleft is left in the umbilical region into which 

 intestine or other organs may protrude. If only intestine protrudes, it pushes 

 up into the umbilical cord, and constitutes a congenital umbilical hernia. If the 

 intestine is included when the cord is ligated, death from strangulation will ensue; 

 hence the danger of this form of hernise. If the urachus remains patulous it may 

 form a urinary fistula. The hypogastric arteries become obliterated and, op- 

 posite Poupart's ligament, have two fossae, one to their outside and one to their 

 inside. Into these fossae direct inguinal herniae may pass. The persistence of the 

 vitelline duct may cause a finger-like projection, called Meeker s diverticulum, on 

 the ileum, about 2 or 3 feet above the ileocaecal valve. Sometimes a band passes 



