582 SPINAL NERVES. 



upper part of the obturator foramen, where it enters the thigh, and divides 

 into an anterior and a posterior branch, separated by the Adductor brevis 

 muscle. 



The anterior branch passes down in front of the Adductor brevis, being covered 

 by the Pectineus and Adductor longus ; and, at the lower border of the latter 

 muscle, communicates with the internal cutaneous and internal saphenous nerves, 

 forming a kind of plexus. It then descends upon the femoral artery, upon which 

 it is finally distributed. 



This nerve, near the obturator foramen, gives off an articular branch to the 

 hip-joint. Behind the Pectineus, it distributes muscular branches to the Adductor 

 longus and Gracilis, and occasionally to the Adductor brevis and Pectineus, and 

 receives a communicating branch from the accessory obturator nerve. 



Occasionally this communicating branch is continued down, as a cutaneous 

 branch, to the thigh and leg ; emerging from the lower border of the Adductor 

 longus, it descends along the posterior margin of the Sartorius to the inner side of 

 the knee, where it pierces the deep fascia, communicates with the long saphenous 

 nerve, and is distributed to the integument of the inner side of the leg, as low 

 down as its middle. When this branch is small, its place is supplied by the 

 internal cutaneous nerve. 



The posterior branch of the obturator nerve pierces the Obturator externus, 

 and passes behind the Adductor brevis to the front of the Adductor magnus, 

 where it divides into numerous muscular branches, which supply the Obturator 

 externus, the Adductor magnus, and occasionally the Adductor brevis. 



The articular branch for the knee-joint perforates the lower part of the 

 Adductor magnus, and enters the upper part of the popliteal space ; descending 

 upon the popliteal artery, as far as the back part of the knee-joint, it perforates 

 the -posterior ligament, and is distributed to the synovial membrane. It gives 

 filaments to the artery in its course. 



The ACCESSORY OBTURATOR NERVE is of small size, and arises either from the 

 obturator nerve near its origin, or by separate filaments from the third and fourth 

 lumbar nerves. It descends along the inner border of the Psoas muscle, crosses 

 the body of the pubes, and passes beneath the Pectineus muscle, where it divides 

 into numerous branches. One of these supplies the Pectineus, penetrating its 

 under surface; another is distributed to the hip-joint; while a third communicates 

 with the anterior branch of the obturator nerve. This branch, when of large 

 size, is prolonged (as already mentioned), as a cutaneous branch, to the leg. The 

 accessory obturator nerve is not constantly found ; when absent, the hip-joint 

 receives branches from the obturator nerve. Occasionally it is very small, and 

 becomes lost in the capsule of the hip-joint. 



The ANTERIOR CRURAL NERVE is the largest branch of the lumbar plexus. It 

 supplies muscular branches to the Iliacus, Pectineus, and all the muscles on the 

 front of the thigh, excepting the Tensor vagince femoris ; cutaneous filaments to 

 the front and inner side of the thigh, and to the leg and foot ; and articular branches 

 to the knee. It arises from the third and fourth lumbar nerves, receiving also a 

 fasciculus from the second. It descends through the fibres of the Psoas muscle, 

 emerging from it at the lower part of its outer border ; and passes down between 

 .it and the Iliacus, and beneath Poupart's ligament, into the thigh, where it 

 becomes somewhat flattened, and divides into an anterior or cutaneous, and a 

 posterior or muscular part. Beneath Poupart's ligament, it is separated from the 

 femoral artery by the Psoas muscle, and lies beneath the iliac fascia. 



Within the pelvis, the anterior crural nerve gives off from its outer side some 

 small branches to the Iliacus, and a branch to the femoral artery, which is 

 distributed upon the upper part of that vessel. The origin of this branch 

 varies ; it occasionally arises higher than usual, or it may arise lower down in 

 the thigh. 



External to the pelvis, the following branches are given off: 



