ANTERIOR CRURAL. FIFTH LUMBAR NERVE. 667 



them, and passing beneath the same aponeurosis. When the vessels pass 

 through the opening in the adductor muscle into the popliteal space, the 

 saphenous nerve separates from them, and is continued downwards beneath 

 the sartorius muscle to the ianer side of the knee ; where, having first 

 given off, as it lies near the inner condyle of the femur, a branch which is 

 distributed over the front of the patella, it becomes subcutaneous by piercing 

 the fascia between the tendons of the sartorius and gracilis muscles. 



The nerve then accompanies the sapheuous vein along the inner side of 

 the leg, and passing in front of the ankle is distributed to the inner side of 

 the foot. In the leg it is connected with the internal cutaneous nerve. 



The distribution of the branches is as follows. 



(a) A communicating branch is given off about the middle of the thigh to join in 

 the interlacement formed beneath the fascia lata by this nerve and branches of the 

 obturator and internal cutaneous nerves. After it has left the aponeurotic covering 

 of the femoral vessels, the internal saphenous nerve has, in some cases, a further 

 connection with one or other of the nerves just referred to. 



(b) The branch to the integument in front of the patella perforates the sartorius 

 muscle and the fascia lata ; and, having received a communicating offset from the 

 internal cutaneous nerve, spreads out upon the fore part of the knee ; and, by uniting 

 with branches of the middle and external cutaneous nerves, forms a plexus plexus 

 patellae. 



(c) A branch to the inner ankle is given off in the lower third of the leg, and 

 descends along the margin of the tibia. 



(d) Filaments from this nerve enter the tarsal ligaments. 



Summary. The anterior crural nerve is distributed to the skin upon the 

 fore part and inner side of the thigh, commencing below the termination of the 

 ilio-inguinal and genito-crural nerves. It furnishes also a cutaneous nerve 

 to the inner side of the leg and foot. All the muscles on the front and outer 

 side of the thigh receive their nerves from the anterior crural, and the pec- 

 tineus is also in part supplied by this nerve, and in part by the obturator. 

 The tensor muscle of the fascia lata is supplied from a different source, 

 viz., the superior gluteal nerve. Lastly, two branches are given from the 

 anterior crural nerve to the knee-joint. 



FIFTH LUMBAR NERVE. 



The anterior branch of the fifth lumbar nerve, having received a fasciculus 

 from the nerve next above it, descends to join the first sacral nerve, and 

 form part of the sacral plexus. The cord resulting from the union of the 

 fifth with a part of the fourth nerve, is named the lumbo-sacral nerve. 



SUPERIOR GLUTEAL NERVE. 



Before joining the first sacral nerve the lumbo-sacral cord gives off from 

 behind the superior gluteal nerve ; this offset leaves the pelvis through the 

 large sacro-sciatic foramen, above the pyriformis muscle, and divides like 

 the gluteal artery into two branches, which are distributed chiefly to the 

 smaller gluteal muscles and tensor of the fascia lata. 



(a) The upper branch runs with the gluteal artery along the origin of the gluteus 

 minimus, and is lost in it and in the gluteus medius. 



(b) The lower branch crosses over the middle of the gluteus minimus, between 

 this and the gluteus medius, and supplying filaments to both those muscles, is con- 

 tinued forwards, and terminates in the tensor muscle of the fascia lata. 



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