THE ARTERIES 193 



tion of the vessel. It passes to the outer side of the tendon of insertion 

 of the psoas parvus muscle and crosses the ilium above the origin of the 

 rectus femoris. Descending the outer side of the last-named muscle it 

 passes between it and the vastus externus and splits into a number of 

 branches which are distributed to the quadriceps extensor cruris. 



(c) The Obturator Artery. — This large vessel may be said to be the 

 continuation of the external division of the internal iliac. It takes a 

 course downwards and backwards, following the course taken by the 

 obturator nerve and vein, being placed between the peritoneum and the 

 ilium. It follows the inferior border of the pyriformis muscle, running 

 along the obturator groove. Passing beneath the obturator internus 

 muscle, it leaves the pelvis by curving downwards through the obturator 

 foramen, and then takes a course backwards between the obturator 

 externus and the inferior surface of the body of the ischium. Finally it 

 divides into a number of branches, which curve downwards and terminate 

 in the biceps and semitendinosus muscles. One of its branches is the 

 Artery to the Corpus Cavernosum. This branch passes backwards and 

 inwards along the inferior surface of the ischium and divides into a 

 number of branches which enter the crus penis. 



The Posterior Dorsal Artery of the Penis is a branch of the artery 

 to the corpus cavernosum. As its name implies, this vessel runs along 

 the upper aspect of the penis. It passes forwards between the ligaments 

 which run from the organ to the pubic symphysis, and anastomoses with 

 the anterior dorsal artery of the penis, which is a branch of the external 

 pudic artery. 



The External Iliac Artery. — There are two of these great vessels, one 

 on either side, and they are the outer members of the pairs of terminal 

 divisions of the posterior aorta. Each commences opposite the fifth lum- 

 bar vertebra and takes a course which is at first downwards and forwards, 

 and then obliquely downwards, backwards, and outwards. It is covered 

 by the peritoneum, which keeps it in position between the psoas parvus 

 and iliacus muscles. Inwardly it is related to the common iliac vein 



2 B 



