196 THE SURGICAL ANATOMY OF THE HORSE 



a. The 'External Pudic Artery. This branch descends on the posterior 

 wall of the inguinal canal, at the back and slightly to the inner side of 

 the spermatic cord. Leaving the canal by the external abdominal ring, 

 it divides into the subcutaneous abdominal artery and anterior dorsal artery 0/ 

 the penis. The former distributes twigs to the superficial inguinal glands, 

 the sheath and scrotum, and also to the skin, and passes forwards in the 

 subcutaneous fascia of the abdomen to the umbilicus, where it anastomoses 

 with the corresponding vessel of the opposite side. The anterior dorsal 

 artery of the penis gives off one or two branches to the scrotum, and 

 passes to the superior aspect of the penis, where it divides into two 

 portions, one of which anastomoses with the posterior dorsal artery of 

 that organ, whilst the other, which is a much longer and more voluminous 

 vessel, passes forwards to the anterior extremity of the penis and is 

 expended in the erectile tissue. 



b. The Posterior Abdominal Artery. — This division of the prepubic 

 artery crosses the direction of the spermatic cord, and passes between 

 the internal oblique and transverse abdominal muscles. It then passes 

 forwards along the outer border of the rectus abdominis, to which 

 muscle it is distributed and in which its terminal ramifications anastomose 

 with those of the anterior abdominal artery. 



II. The Profunda^ or Deep Femoral Artery. — -This large branch forms 

 a common trunk at its origin with the prepubic artery. After separating 

 from the latter it passes backwards between the iliacus and pectineus 

 muscles and then between the latter and the obturator externus. It then 

 passes beneath the adductor muscles and divides into ascending branches, 

 which anastomose with branches of the ischiatic artery, and descending 

 branches which contract anastomoses with the terminations of the obtu- 

 rator artery. This vessel gives off collateral branches which supply the 

 pectineus, gracilis, and both the adductor muscles, whilst its terminal 

 branches are distributed to the biceps femoris. 



III. Muscular Branches. — The largest of these leaves the parent vessel 

 opposite where the profunda artery is given off. It passes forwards 



