664 



THE LUMBAR PLEXUS. 



This nerve is sometimes smaller than usual, and ends in filaments which perforate 

 the capsule of the hip-joint. When it is altogether wanting, the hip-joint receives 

 branches from the obturator nerve. 



Summary. The obturator nerve and accessory obturator give branches to 

 the hip and knee joint?, also to the adductor muscles of the thigh, and, in 

 some cases, to the pecfcineus. Occasionally a cutaneous branch descends to 

 the inner side of the thigh, and to the inner and upper part of the leg. 



Fir. 439. 



ANTERIOR CRURAL NERVE. 



This nerve is the largest branch of the lumbar plexus, and is derived 

 piincipally from the third and fourth lumbar nervea, but in part also from 



the second. Emerging from the outer 

 border of the psoas muscle, near its lower 

 part, it descends into the thigh in the 

 groove between that muscle and the iliacus, 

 and, therefore, to the outside of the femoral 

 blood-vessels. It now becomes flattened 

 out and divides into two parts, one of 

 which is cutaneous, while the other is dis- 

 tributed to muscles. 



Fig. 439. DEEP NERVES OP THE ANTERIOR AND 

 INNER PART OF THE THIGH (from Sappey after 

 Hirschfeld and Leveille). 



1, anterior crural nerve ; 2, branches given to 

 the iliacus muscle ; 3, branch to the lower pa't of 

 the psoas ; 4, large musculo-cutaneous branches, 

 divided to show the deeper nerves ; 5 and 6, mus- 

 cular filaments from the small musculo-cutaneous ; 

 7. origin of the cutaneous branches ; 8, communi- 

 cating filament of the internal cutaneous nerves ; 

 9, branches to the rectus ; 10, branches to the 

 vustus externus ; 11, branches to the vastus inter- 

 ims ; 12, internal saphenous nerve ; 13, its patellar 

 branch; 14, its continuation down the leg ; 15, 

 obturator nerve ; 16, branch from the obturator 

 nerve to the adductor longus ; 17, branch to the 

 adductor brevis ; 1 8, 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 trunk ; 21, 

 its union with the first sacral nerve ; 22, 22, lum- 

 bar and sacral part of the sympathetic nerve ; 23, 

 external cutaneous nerve from the lumbar plexus. 



Branches of the trunk. The branches 

 given from the anterior crural nerve within 

 the abdomen are few and of small size. 



(a) The iliacus receives three or four small branches, which are directed outwards 

 from the nerve to the fore part of the muscle. 



(b) The nerve of the femoral artery is a small branch which divides into numerous 

 filaments upon the upper part of that vessel. It sometimes arises lower down than 

 i' ;nal in the thigh. It may, on the other hand, be found to take origin above the 

 ordinary position ; and in this case it proceeds from the middle cutaneous nerve, 



