THE ANTERIOR CRURAL NERVE. 



521 



(e) The branch to the rectas femoris (3, 4 I) enters the posterior surface of its 

 muscle : from this nerve, and from some of the other muscular branches, twigs are 

 sent, in company with a branch of the external circumflex artery, to the hip-joint. 



(/) The nerve to the vastm externus (3, 4 /), of considerable size, descends with 

 a large branch of the external circumflex artery along the anterior border of the 

 muscle, and sends a filament to the knee-joint. 



(ff) Two or three branches (3, 4 /) penetrate the crureus muscle on its anterior 

 surface, and from the most internal of these a filament can be traced, under cover of 

 the anterior border of the vastus internus muscle, to the subcrnreus. the periosteum 

 of the lower end of the femur, and the synovial membrane of the knee-joint. 



Fig. 209. DEEP NERVES OP THE ANTERIOR AND INNER PART OF 

 THE THIGH. (From Sappey, after Hirschfeld and Leveille.) | 



1, anterior crural nerve ; 2, branches to the iliacus muscle ; 

 3, branch to the lower part of the psoas ; 4, internal and middle 

 cutaneous nerves, divided to show the deeper branches ; 5, 6, 

 nerves to the pectineus ; 7, cutaneous filament from the last ; 8, 

 posterior branch of the internal cutaneous nerve ; 9, branch to the 

 rectus ; 10, branch to the vastus externus ; 11, branch to the 

 vastus internus ; 12, internal saphenous nerve ; 13, its patellar 

 branch ; 14, its continuation to the leg ; 15, obturator nerve ; 16, 

 branch to the adductor longus; 17, branch to the adductor brevis ; 

 18, branch to the gracilis ; from this a filament is prolonged 

 downwards, to unite with the plexus formed by the union of 

 branches from the internal cutaneous and internal saphenous 

 nerves ; 19, deep branch of the obturator nerve to the adductor 

 magnus ; 20, lumbo-sacral cord ; 21, its union with the first sacral 

 nerve ; 22, 22, lumbar and sacral parts of the sympathetic nerve ; 

 23, external cutaneous nerve. 



(7^) The nerve of the vastus internus (3, 4 I) runs 

 downwards with the internal saphenous nerve beneath 

 the aponeurosis covering the femoral vessels, giving 

 several branches to the upper part of its muscle ; it 

 enters the latter about the middle of the thigh, and 

 from its lower end a considerable twig is continued 

 to the knee-joint, in company with the deep branch 

 of the anastomotic artery. 



(i) Internal saphenous nerve. The internal or 

 long saphenous (3, 4/) is the largest of the branches of 

 the anterior crural nerve. It is deeply placed as far as 

 the knee, but is subcutaneous in the rest of its extent. 



In the thigh, it accompanies the femoral vessels, 

 lying at first to their outer side, but lower down 

 gradually crossing over the artery, and passing 

 beneath the same aponeurosis. When the vessels 



pass through the opening in the adductor magnus muscle into the popliteal space, 

 the saphenous nerve separates from them, and is continued beneath the sartorius 

 muscle to the inner side of the knee ; here, having first given off', as it lies near thu 

 inner condyle of the femur, a branch which is distributed over the front of the patella, 

 it becomes subcutaneous by piercing the fascia at the lower border of the sartorius. 



The nerve then accompanies the saphenous vein along the inner side of the leg, 

 and, passing in front of the inner ankle, terminates on the inner side of the meta- 

 tarsal region of the foot. In the leg it is connected with the posterior branch of the 

 internal cutaneous nerve. 



The distribution of its branches is as follows : 



A communicating branch is given off about the middle of the thigh to join in the 



