THE PERIPHERAL NERVOUS SYSTEM. 397 
and fifth nerves, most of its fibres coming from the fifth. It 
passes caudoventrad between the iliopsoas and psoas minor and 
accompanies the iliolumbar artery across the ventral surface of 
the iliopsoas. It pierces the abdominal wall in company with 
the artery and passes onto the cranial border of the thigh. Its 
terminal branches are distributed to the integument along with 
the branches of the iliolumbar artery,—supplying the lateral 
surface of the femur and extending as far as the knee. 
6. N. femoralis (/).—The femoral is a large nerve which 
rises by strong roots from the fifth and sixth lumbar nerves. 
It gives branches to the iliopsoas (8) and passes through that 
muscle to its ventral surface. It leaves the abdominal cavity 
lying on the ventral surface of the iliopsoas, and at the point 
where it pierces the abdominal wall it divides into three (or 
four) branches. One (or two) of these pass to the sartorius 
muscle. Another passes between the rectus femoris and vastus 
medialis muscles, and divides into numerous branches which 
supply these muscles and the vastus intermedius. 
The third branch of the femoral is N. saphenus or the long 
saphenous nerve (Fig. 127, g, page 310). This passes distad 
along with the femoral artery and vein, giving a few twigs to 
the integument. Where the long saphenous artery (/) sep- 
arates from the femoral artery the nerve follows the former and 
passes with it along the medial side of the lower leg. At the 
knee and in the lower leg it gives off a number of cutaneous 
branches, and finally divides just distad of the middle of the 
lower leg into two main branches. Both of these pass to the 
concavity of the ankle-joint and divide into fine branches, which 
form a sort of plexus on the ankle and dorsal surface of the 
foot; branches from this can be traced almost to the toes. 
7. N. obturatorius (Fig. 162, g).—The obturator nerve 
arises from the connecting band between the sixth and seventh 
nerves. It lies at first laterad, then dorsad, of the common 
iliac vein, and passes almost directly caudad to the cranial 
border of M. obturator internus (15). Here it turns sharply 
laterad about the pubis, and passes through the obturator 
foramen. It gives twigs to the obturator externus muscle, and 
