

THE LUMBAR NERVES 955 



magnus, where it divides into numerous muscular branches which are distributed 

 to the Adductor magnus and the Adductor brevis when the latter does not receive 

 a branch from the anterior division of the nerve. It usually gives off an articular 

 filament to the knee-joint. 



The articular branch for the knee-joint is sometimes absent; it either perforates 

 the lower part of the Adductor magnus, or passes through the opening which trans- 

 mits the femoral artery, and enters the popliteal fossa; it then descends upon the 

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

 oblique popliteal ligament, and is distributed to the synovial membrane. It gives 

 filaments to the popliteal artery. 



The Accessory Obturator Nerve (n. obturatorius accessorius) (Fig. 823) is present 

 in about 29 per cent, of cases. It is of small size, and arises from the ventral divi- 

 sions of the third and fourth lumbar nerves. It descends along the medial border 

 of the Psoas major, crosses the superior ramus of the pubis, and passes under the 

 Pectineus, where it divides into numerous branches. One of these supplies the 

 Pectineus, penetrating its deep surface, another is distributed to the hip-joint; 

 while a third communicates with the anterior branch of the obturator nerve. 

 Occasionally the accessory obturator nerve is very small and is lost in the capsule 

 of the hip-joint. When it is absent, the hip-joint receives two branches from the 

 obturator nerve. 



The Femoral Nerve (n. femoralis; anterior crural nerve) (Fig. 827), the largest 

 branch of the lumbar plexus, arises from the dorsal divisions of the second, third, 

 and fourth lumbar nerves. It descends through the fibers of the Psoas major, 

 emerging from the muscle at the lower part of its lateral border, and passes down 

 between it and the Iliacus, behind the iliac fascia; it then runs beneath the inguinal 

 ligament, into the thigh, and splits into an anterior and a posterior division. Under 

 the inguinal ligament, it is separated from the femoral artery by a portion of the 

 Psoas major. 



Within the abdomen the femoral nerve gives off small branches to the Iliacus, 

 and a branch which is distributed upon the upper part of the femoral artery; the 

 latter branch may arise in the thigh. 



In the thigh the anterior division of the femoral nerve gives off anterior cuta- 

 neous and muscular branches. The anterior cutaneous branches comprise the 

 intermediate and medial cutaneous nerves (Fig. 825). 



The intermediate cutaneous nerve (ramus cutaneus anterior; middle cutaneous 

 nerve) pierces the fascia lata (and generally the Sartorius) about 7.5 cm. below 

 the inguinal ligament, and divides into two branches which descend in immediate 

 proximity along the forepart of the thigh, to supply the skin as low as the front 

 of the knee. Here they communicate with the medial cutaneous nerve and the 

 infrapatellar branch of the saphenous, to form the patellar plexus. In the upper 

 part of the thigh the lateral branch of the intermediate cutaneous communicates 

 with the lumboinguinal branch of the genitofemoral nerve. 



The medial cutaneous nerve (ramus cutaneus anterior; internal cutaneous nerve) 

 passes obliquely across the upper part of the sheath of the femoral artery, and divides 

 in front, or at the medial side of that vessel, into two branches, an anterior and a 

 posterior. 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 

 supplies the integument as low down as the medial side of the knee; the other 

 crosses to the lateral side of the patella, communicating in its course with the infra- 

 patellar branch of the saphenous nerve. The posterior branch descends along the 

 medial border of the Sartorius muscle to the knee, where it pierces the fascia lata, 

 communicates with the saphenous nerve, and gives off several cutaneous branches. 

 It then passes down to supply the integument of the medial side of the leg. Beneath 

 the fascia lata, at the lower border of the Adductor longus, it joins to form a plexi- 



