77//V OHTl'UM'OR A'/sATA,' 1)11 



The posterior branch descends along the posterior liorder of t lie sartorius. and it 

 rives off a liraneli which passes beneath tliat tnusele to unite with twigs from the 

 saphcnousand from t lie superficial division of the obturator nerve, forming with them 

 t he subsartorial plexus which lies on the roof of t he adductor ( Hunter's )canal. At 

 the inner side of (lie knee the nerve pierces the deep fascia and it descends to the 

 middle of the calf (figs, (is! I and (i'.)l). 



The deep terminal branches are six in number, one cutaneous branch, the 

 saphenous. and live muscular branches. The brandies radiate from the termination 

 of the trunk of the femoral (anterior crural) nerve, and t hey are arranged in the 

 following order from within outward: the saphenous nerve, the nerve to the vastus 

 medialis. the nerve to the articularis genu (subcruretis), the nerve to the vastus inter- 

 medius (crureus),the nerve to the vastus lateralis, and the nerve to the rectus fenioris. 



The saphenous nerve passes down through Searpa's triangle along the outer 

 side of the femoral artery. At the apex of the triangle it entersthe adductor (Hunter's) 

 canal and descends through it, lying first to the outer side, then in front, and finally 

 t n I he inner side of the artery (fig. 690). After emerging from the lower end of the 

 canal, accompanied by the superficial branch of the genu suprema (anastomotic) 

 artery, it passes between the posterior border of the sartorius and the anterior border 

 of the tendon of the gracilis, and, becoming superficial, it enters into relationship 

 with the great saphenous vein and descends with it along the inner border of the upper 

 two-thirds of the tibia (fig. 691). It crosses the inner surface of the lower third of the 

 tibia, passes in front of the internal malleolus, and runs forwards along the inner 

 border of the foot to the ball of the great toe. 



While it is in the adductor (Hunter's) canal it gives off a twig to the subsartorial 

 plexus. Before it passes from under cover of the sartorius it gives off an infra- 

 patellar branch, which pierces the sartorius just above the knee and passes outwards to 

 the patellar plexus. After it becomes superficial it supplies the integument on the 

 inner side of the leg and foot, and it anastomoses, in the foot, with the medial dorsal 

 cutaneous branch of the superficial peroneal (musculo-cutaneous) nerve. 



The nerve to the vastus medialis accompanies the saphenous nerve in the 

 femoral trigone (Searpa's triangle), lying to its outer side. At the upper end of 

 the adductor canal it passes beneath the sartorius, external to the roof of the canal, 

 and enters the inner surface of the vastus medialis. It sends a twig down to the 

 knee-joint. 



The nerve to the articularis genu (subcrureus), usually a terminal branch of 

 the femoral, frequently arises from the nerve to the vastus intermedius. It pa 

 between the vastus medialis and the vastus intermedius to the lower third of the 

 thigh, where it supplies the articularis genu and sends a branch to the knee-joint. 



The nerve to the vastus intermedius (crureus) is represented by two or three 

 branches which enter the upper part of the muscle. One of them frequently sends 

 a twig to the knee-joint. 



The nerve to the vastus lateralis passes downwards behind the rectus and 

 along the anterior border of the vastus lateralis accompanied by the descending 

 branch of the external circumflex artery. It also sends a branch to the knee-joint. 



The nerve to the rectus femoris (fig. 690) enters the deep surface of that muscle, 

 having previously given off a twig to the hip-joint which accompanies the ascending 

 branch of the external circumflex artery. 



The Obturator Nerve contains fibres from the anterior divisions of the second, 

 third, and fourth lumbar nerves, but its largest root is derived from the third nerve 

 (figs. 6S8 and 693) . It sometimes receives fibres from the first and third lumbar nerves. 

 It emerges from the inner border of the psoas at the posterior part of the brim of 

 the pelvis, where it lies in close relation with the lumbo-sacral trunk of the plexus, 

 from which it is separated by the ilio-lumbar artery. Immediately after its exit 

 from the psoas it pierces the pelvic fascia, crosses the outer side of the internal iliac 

 vessels and the ureter, and runs forwards in the extraperitoneal fat, below the 

 obliterated hypogastric artery and along the upper part of the inner surface of the 

 obturator internus to the upper part of the obturator foramen, where it passes 

 .through the obturator canal below the so-called horizontal raimis of the pubis and 

 'above the obturator membrane, into the upper part of the thigh. It is accompanied 

 in Ihe pelvis and the obturator canal by the obturator artery, which lies at a lower 

 level than the nerve, and it divides in the obturator canal into two branches, an 

 anterior and a posterior. 



