The branches to the pectinwus are directed inwards behind the femoral vessels, and in their course to this muscle generally send a few filaments to the psoas.
Tbe muscular branches arise ex ternal to the internal saphxnus nerve, and behind the superficial already described : and are from within outwards : Branches for the vastus internus and crureaus : branch for the rectus : and branches for the vastus externus, which are the deepest of all.
The branch for the vastus internus (short saphmnus), taking its origin in close contact with the internal saphmnus, from which it not unfrequently arises, is directed in com pany with, but external to it, along with the femoral artery. It separates a little below the middle of the thigh from the vessels, and is directed to the external aspect of the vastus internus, to enter it at its lower one third ; but before so doing gives off a superficial ar ticular branch, which passes in front of the outer border of Hunter's canal ; in this situa tion occasionally communicating either with the cutaneous branch of the obturator, or the outer branch of the accessory, saphmnus; crosses through the superficial muscular fibres of the vastus to its aponeurotic termination, which it perforates. It is then reflected for wards, upwards, and outwards, and terminates in two or three filaments, one of which passes behind the ligamentum patella, entering the anterior part of the knee-joint ; the others pass in front of the patella, to supply the periosteum and skin over it.
The nerve for the crurivus, shorter than that for the vastus internus, enters the upper and inner part of the muscle, extends as far as its lower part, and gives off filaments to the deep-seated portion of the muscle (the sub crurmus) to the periosteum and upper part of the synovial capsule.
The branch ji,r the rectus enters the upper part of its posterior aspect, and divides into a superior branch which passes transversely out wards, and a long vertical branch which passes along its inner side to the lower portion.
7'he branch for the vastus externus frequently arising in company with that for the rectus, is directed downwards and outwards between that muscle and the crurmus, and, in company with the descending branches of the external circumflex artery, enters its inner aspect by two or three divisions, having previously given off a superficial articular branch. This filament,
the analogue of the corresponding branch of the vastus internus, creeps beneath the su perficial muscular fibres, and near the pa tella becomes cutaneous, some of the ter minal filaments passing behind the outer part of the ligamentum patella, others over the patella, where they are lost in the skin and periosteum.
The saphcenus nerve (crag*, manifest), the most internal of the deep-seated branches, and arising behind and external to the mid dle cutaneous, is the largest branch of the crural. It passes downwards and outwards towards the femoral artery, and, about two or three inches below Poupart's ligament, en ters its sheath. The nerve first lies outside anti behind the artery ; but a little before the vessel enters Hunter's canal it gets anterior to it. During the course of the artery down wards and outwards, to enter the ham, the nerve inclines forwards and inwards, and quits the canal, in company with the anastomotic ar tery, a little above the level at which the fe moral vein and artery pass out. It now follows the course of the sartorius lying behind it, to the inner condyle, and one or two inches above the head of the tibia is placed between that muscle and the gracilis, and gives off', before continuing its course, the cutaneous tibial or re flected branch. This nerve first runs_ parallel for a short distance with the tendons of the two muscles, then sweeps downwards, for wards, and slightly upwards over the fascia covering them and their tendinous expansions, and across the spine of the tibia to the skin at the upper and outer part of the leg, about two or three inches below the head of the tibia, communicating above with the internal cutaneous.