CRURAL NERVE. 471 



ligament. It then pierces the fascia lata at about two inches below 

 the anterior superior spine of the ilium, and divides into two branches, 

 anterior and posterior. The posterior branch crosses the tensor vaginae 

 femoris muscle to the outer and posterior side of the thigh, and supplies 

 the integument in that region. The anterior nerve divides into two 

 branches which are distributed to the integument upon the outer bor- 

 der of the thigh, and to the articulation of the knee. 



The GENITO-CRURAL proceeds also from the second lumbar nerve. 

 It traverses the psoas magnus from behind forwards, and runs down 

 on the anterior surface of that muscle and beneath its fascia to near 

 Poupart's ligament, where it divides into a genital and a crural branch. 

 The genital branch (n. spermaticus seu pudendus externus) crosses the 

 external iliac artery to the internal abdominal ring and descends 

 along the spermatic canal, lying behind the cord to the scrotum, where 

 it divides into branches which supply the spermatic cord and cremaster 

 in the male, and the round ligament and external labium in the female. 

 At the internal abdominal ring this nerve sends off a branch which 

 after supplying the lower border of the internal oblique and transver- 

 salis, is distributed to the integument of the groin. The crural branch 

 (lumbo-inguinalis), the most external of the two, descends along the 

 outer border of the external iliac artery and, crossing tbe origin of the 

 circumflex ilii artery, enters the sheath of the femoral vessels in front 

 of the femoral artery. It pierces the sheath below Poupart's ligament, 

 and is distributed to the integument of the anterior aspect of the thigh 

 as far as its middle. This nerve is often very small, and sometimes 

 communicates with one of the cutaneous branches of the crural nerve. 



The CRURAL, or FEMORAL NERVE, is the largest of the divisions 

 of the lumbar plexus ; it is formed by the union of branches from the 

 second, third, and fourth lumbar nerves, and, emerging from beneath 

 the psoas muscle, passes downwards in the groove between it and 

 the iliacus, and beneath Poupart's ligament into the thigh, where 

 it spreads out and divides into numerous branches. At Poupart's 

 ligament it is separated from the femoral artery by the breadth of the 

 psoas muscle, which at this point is scarcely more than half an inch 

 in diameter, and by the iliac fascia, beneath which it lies. 



Branches. While situated within the pelvis the crural nerve gives 

 off several muscular branches to the iliacus, and one to the psoas. On 

 emerging from beneath Poupart's ligament the nerve becomes flattened 

 and divides into numerous branches, which may be arranged into, 



Cutaneous, 



Muscular, 



Branch to the femoral sheath, 



Short saphenous nerve, 



Long saphenous nerve. 



The Cutaneous nerves (middle cutaneous) two in number, proceed 



