THE LUMBO8ACRAL PLEXUS 1053 



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. 

 In the thigh the following branches are given off: 



From the Anterior Division. From the Posterior Division. 



Middle cutaneous. Long saphenous. 



Internal cutaneous. Muscular. 



Muscular. Articular. 



The middle and internal cutaneous branches of the femoral nerve are the 

 rami cutanei anteriores n. femoralis of the BNA. 



The middle cutaneous nerve (Figs. 770 and 771) pierces the fascia lata (and 

 generally the Sartorius) about three inches (8 cm.) below Poupart's ligament, and 

 divides into two branches (Fig. 770), which descends in immediate proximity 

 along the fore part of the thigh, to supply the integument as lo\v as the front of the 

 knee. Here they communicate with the internal cutaneous nerve and the patellar 

 1 ranch of the internal saphenous nerve, to form the patellar plexus. In the upper 

 part of the thigh the outer division of the middle cutaneous nerve communicates 

 with the femoral branch of the genitofemoral nerve. 



The internal cutaneous nerve (Fig. 770) passes obliquely across the upper part 

 of the sheath of the femoral artery, and divides in front or at the inner side of that 

 vessel into two branches, anterior and posterior or internal. 



The internal cutaneous nerve, before dividing, gives off a few filaments, which pierce the 

 fascia' lata (accompanying the long saphenous vein) to supply the integument of the inner side 

 of the thigh. One of these filaments passes through the saphenous opening; a second becomes 

 subcutaneous about the middle of the thigh (Fig. 770); and a third pierces the fascia at its 

 lower third (Fig. 770). 



The anterior branch runs downward on the Sartorius, perforates the fascia lata 

 at the lower third of the thigh, and divides into two branches, one of which supplies 

 the integument as low down as the inner side of the knee; the other crosses to the 

 outer side of the patella, communicating in its course with the nervus cutaneus 

 patellae, a branch of the long or internal saphenous nerve. The posterior or 

 internal branch descends along the inner border of the Sartorius muscle to the knee, 

 where it pierces the fascia Tata, communicates with the long saphenous nerve, 

 and gives off several cutaneous branches. It then passes down to supply the integ- 

 ument of the inner side of the leg. Beneath the fascia lata, at the lower border 

 of the Adductor longus, it joins with branches of the long saphenous and obturator 

 nerves to form a plexiform network (subsartorial plexus) (Fig. 771). When the 

 communicating branch from the obturator nerve is large and continued to the 

 integument of the leg, the internal branch of the internal cutaneous is small and 

 terminates in the plexus, occasionally giving off a few cutaneous filaments. 



The Muscular Branches of the Anterior Division (rami musculares). The nerve 

 to the Pectineus arises from the femoral nerve immediately below Poupart's liga- 

 ment, and passes inward behind the femoral sheath to enter the anterior surface 

 of the muscle; it is often duplicated. The nerve to the Sartorius arises in common 

 with the middle cutaneous. 



The long or internal saphenous nerve (n. saphenm} (Figs. 770 and 771) is the 

 largest of the cutaneous branches of the femoral nerve. It approaches the femoral 

 artery where this vessel passes beneath the Sartorius, and lies in front of it, beneath 

 the aponeurotic covering of Hunter's canal, as far as the opening in the lower part 

 of the Adductor magnus. It then leaves the artery, arid proceeds distally along the 

 inner side of the knee, beneath the Sartorius muscle, pierces the fascia lata opposite 

 the interval between the tendons of the Sartorius andGracilis muscles, and becomes 



