The nerve in its course within the pelvis is situated behind the iliac division of the trans versalis fascia, external to the iliac artery, and gives off a few branches to the psoas and ili acus. Outside the sheath of the femoral vein and artery it is separated from the latter by the intervention of' the psoas muscle.
The terminal branches may be divided into superficial and deep ; the first consisting of the internal, and middle cutaneous, and branches to the femoral vessels and pectineeus : the second of branches to the quadriceps extensor cruris, and the cutaneous branch of the inner and anterior part of the knee and leg, viz. the in ternal saphanus.
The internal cutaneous nerve (internal mus culo-cutaneous) directed along the inner bor der of the sartorius muscle, perforates the fascia at the lower third of the leg, occa sionally perforating the sartorius Wore so doing. Having given off several cutaneous branches, which form a connexion with the cu taneous branch of the obturator in this situa tion, it continues its course towards the lower and inner part of the thigh, having previously communicated with a branch perforating the sartorius, and coining from the internal sa phmnus. From the thigh it passes along the inner edge of the patella, describing a curve, and sending some terminal filaments from its concavity upwards to unite with the middle cutaneous : others, from its convexity down wards, to communicate with the reflected branch of the saphmnus itself, and also its accessory branch.
The accessozy saphrenus nerve (Cruveilhier) takes its origin from the internal cutaneous ; froni the anterior crural in company with the latter ; or from the trunk of the saphmnus it self. It soon divides into a superficial internal branch, which pasqes from within the sheath of the sartorius muscles over the femoral vessels, and adductor longus, and at the junc tion of about the upper with the middle third of the thigh meets with the internal saphmna vein, which it accompanies as far as the knee joint, in which situation it communicates with the internal saphmnus and cutaneous branch of the obturator. The external branch, situ ated behind the level of' the superficial, is directed inwards to the femoral artery, runs along its outer part in close contact with it, and accompanies the vessel in Hunter's canal to its lower extremity. It then quits the
artery, is directed in front of the tendon of the adductor magnus, to the upper part of the internal condyle of the femur, where it becomes cutaneous, anastomosing with the internal cutaneous above, with the reflected branch of the sapheenus below, and sending cutaneous branches over the inner and middle part of the patella. This branch has been termed by Cruveilhier the satellite nerve of the femoral artery : and the superficial branch might with equal propriety be denominated the satellite nerve of the saphwna vein. The accessory sapheenus is subject to considerable variation, both as to size and origin.
The nziddle cutaneous nez ve perforates the fascia three or four inches below Poupart's ligament, crosses the sartorius muscle, and is directed over the inner part of the rectus to terminate in the cuticle over the front of the patella, anastomosing above with the external cutaneous nerve, and below with the internal cutaneous and accessory saphmnus. It fre quently divides about the middle of the thigh into two branches, which run parallel with each other. The internal and middle cuta neous nerves not unfrequently perforate the sartorius muscle before becoming cutaneous, the first at the middle, the second at its upper part. They are consequently described also as the inferior perforating cutaneous, and the superior perforating cutaneous.
The nerve to the femoral vessels is very de licate, and arises internal to the internal cu taneous, sometimes however coming off' from the lumbar plexus. It is directed downwards and inwards to the femoral vessels, and di vides into a series of filaments, one or two of which are directed through the cribriferm fascia to the saplimna vein, along which they pass in a tortuous manner till lost by com municating with the internal branch of the accessory saphmnus, about the middle of the thigh. The remainder pass, some behind and some in front of the femoral vessels, and ter minate at the lower third of the thigh, by uniting with the external branch of the acces sory saphmnus.