182 EQtJINE ANATOMY. 



the psoas parvus above the origin of the anterior rectus 

 muscle, and ends in the patellar muscles. 



Veins. — The internal iliac formed by the iliaco-f em- 

 oral, obturator, iliaco-muscular, gluteal, lateral sacral 

 and internal pudic, unite with the external iliac to form 

 the pelvi-crural trunk. 



Lymphatics. — Empty into the sub-lumbar ganglions. 



IVEUROLOGY. 



Sacral nerves — Five pairs. Superior branches 

 like those of the other spinal nerves. The inferior 

 branch co-operates to form the lumbo-sacral plexus (see 

 abdominal extremity, page 63) by the first, second 

 and third pairs; the fourth constitutes the internal 

 pudic, and the fifth the anal or hemorrhoidal nerve. 



Sacral portion of the sympathetic. — Formed by 

 four ganglions united by branches communicating 

 with the spinal sacral nerves, and at the posterior ex- 

 tremity of which starts a last nerve, the end of the 

 sympathetic cordon, wliich terminates in various ways. 



