THE LOWER EXTREMITY, ANTERIOR. 583 



The anterior branch supplies the pectineus, adductor brevis 

 and longus, and the gracilis muscles, the hip joint, and 

 the integument at the middle of the inner side of the 

 thigh. 



The posterior branch descends through the obturator ex- 

 ternus muscle, then between the adductor brevis and mag- 

 nus, and is continued as a long, slender filament through 

 the lower part of the last muscle into the popliteal space, 

 through which it descends on the anterior surface of the 

 popliteal vessels to the posterior ligament of the knee 

 joint. 



The posterior branch supplies the obturator externus, 

 and adductor magnus muscles, the hip and knee joints. 



The Accessory Obturator Nerve. Fig. 107. 



For the formation, course, and distribution of this nerve, 

 see page 536. 



The Obturator Artery. Figs. 112, 114, 120. 



This is a branch from the anterior division of the inter- 

 nal iliac artery. For its course and branches within the 

 pelvis, see page 547. 



The artery appears with the nerve at the upper margin 

 of the obturator externus muscle, which it perforates, and 

 divides into an internal and an external branch. These 

 course along the internal and external margins of the 

 obturator foramen respectively, anastomose with each other 

 at the lower border of the foramen and supply branches to 

 the adjacent muscles. In addition the internal branch 

 anastomoses with the internal circumflex, and the external 

 branch passes outward below the hip (which it supplies) 

 and terminates in small branches which anastomose with 

 the terminal branches of the sciatic artery. 



