SACRAL NERVES. 523 



Saphenous, which has a different destination. It accompanies 

 the great artery of the thigh to the place where it perforates 

 the Adductors ; it there separates from the artery, and passes 

 over the tendon of the Adductors, under the sartorius muscle ; 

 thence it continues, with the great saphena vein on the inside 

 of the leg, to the internal ankle ; sending branches to the 

 integument, in its course. It terminates in skin and cellular 

 substance on the upper and internal surface of the foot. 

 Another branch is generally found coming from the outer 

 crural called the short saphenous or accessory nerve of the 

 saphenous. It anastomoses with the obturator and with the 

 long saphenous nerve. It sends off some cutaneous branches in 

 the middle of the thigh behind the internal saphena vein, and 

 distributes filaments to the skin at the inner surface of the knee. 

 When this nerve is absent its place is supplied by branches 

 from the long saphenous. 



The Sacral Nerves 



Are composed of those cords of the cauda equina which 

 remain after the formation of the lumbar nerves. They are fre- 

 quently stated to consist of five or six pairs, four of which pass 

 through the foramina of the sacrum and the fifth between the 

 sacrum and the os coccygis.* The cords of which they are 

 respectively composed arise by anterior and posterior fasciculi. 

 When they have arrived opposite to the foramina of the sacrum, 

 through which they are to pass, a ganglion is formed, at which 

 they unite ; they then divide into anterior and posterior 

 branches.f The uppermost of the anterior branches are large, 

 and pass through the anterior foramina of the sacrum. The 

 posterior are small, and go through the posterior foramina. 



The Posterior Branches are generally spent upon the mus- 

 cles which lie on the sacrum and posterior parts of the pelvis, 

 externally. 



The anterior branches of the three first nerves send ramifica- 

 tions to the sympathetic. They unite to each other, and are 



* The sixth pair, when they exist, proceed in a groove in the os coccygis. 

 f The ganglions of the fourth and fifth nerves are extremely small, and not 

 so near the foramina as those of the others. 



