576 THE ARTERIES 



of the incision is not made higher than the superficial, the artery will not be endan- 

 gered. At times, however, the artery is given off from the })udic lower than 

 normal. Its division may then be unavoidable. 



When the artery is given off, as it occasionally is, from the accessory pudic, it 

 pierces the anterior layer of the triangular ligament higher up, and is out of danger 

 in the ordinary low operation of lateral lithotomy. Further, the artery of the 

 bulb may be absent on one side, smaller than usual, or double. 



In the female, the artery of the bulb, smaller than in the male, ends in the 

 bulb of the vestibule. 



{I)) The artery of the crus is usually given off from the pudic a little higher 

 than the artery of the bulb. It makes at once for the ramus of the pubes, per- 

 forates the anterior layer of the triangular ligament close to the bone, and enters 

 the crus penis (figs. 370a, 371). This artery has to be divided in the operation for 

 the removal of the wdiole of the penis by dissecting off the crura from the rami of 

 the pubis and ischium. Its situation close to the bone at times gives rise to some 

 little trouble in securing it. A small additional artery to the corpus spongiosum is 

 occasionally given off from this branch and then contributes to the supply of that 

 structure and inosculates with branches from the artery to the bulb. 



In the female, the artery ends in the crus clitoridis. 



(c) The dorsal artery of the penis (fig. 371), the termination of the pudic, 

 passes upwards between the two layers of the triangular ligament in the substance 

 of the compressor urethrse muscle; then, turning forwards, perforates the anterior 

 layer of the triangular ligament, near its apex, a little to one side of the central 

 apical opening for the dorsal vein. It then passes between the two layers of the 

 suspensory ligament of the penis, and descends along the dorsum of that organ, 

 the single centrally placed dorsal vein separating it from the artery of the opposite 

 side. The dorsal nerve lies to the outer side of the artery, and, still more external, 

 the deep external pudic branch of the common femoral artery. At the glans the 

 dorsal artery forms an anastomotic chain around the corona with the vessel of the 

 opposite side. The superficial external pudic branch of the femoral at times may 

 take the place of the dorsal artery. Occasionally the dorsal artery is found to 

 arise from the inferior vaginal; that is, from an enlarged branch of the vessel known 

 as the accessory pudic (see page 570). 



In the female, the termination of the pudic is called the dorsal artery of the 

 clitoris. 



The dorsal artery gives branches to — (a) The corpus cavernosum; (6) the skin 

 of the penis; (c) the glans penis; and in the female, (d) the glans and prepuce 

 of the clitoris. 



THE EXTERNAL ILIAC ARTERY 



The external iliac artery — the larger in the adult of the two vessels into which 

 the common iliac divides opposite the lumbo-sacral articulation — extends from this 

 spot along the brim of the pelvis, lying upon the inner border of the psoas muscle, 

 to the lower margin of Poupart's ligament, where, midway between the anterior 

 superior spine of the ilium and the symphysis pubis, it passes into the thigh, and 

 takes the name of the femoral. 



It measures three and a half to four inches (10 cm.) in length. The course of 

 the vessel is indicated by a line drawn from half an inch below and a little to the 

 left of the umbilicus, to a point a little internal to the centre of Poupart's liga- 

 ment, that is, to a spot midway between the symphysis pubis and the anterior 

 superior spine of the ilium. If this line is divided into thirds, the lower two 

 thirds indicate the situation of the external iliac, the upper third the common 

 iliac. The external iliac vein, the continuation upwards of the femoral vein 

 from the thigh, lies to the inner side of the artery, but on a slightly lower plane, 

 and just before its termination gets a little behind the artery on the right side. 



Relations. — In front, the artery together with the vein is covered by the 

 parietal peritoneum descending from the abdomen into the pelvis, and by a layer 

 of condensed subperitoneal tissue, known as Abernethy's fascia. It is crossed by 

 the termination of the ileum on the right side, and by the sigmoid flexure on the 



