724 THE NEKVOUS SYSTEM. 



the adductor brevis. The branch to the obturator externus arises before the nerve 

 enters the muscle, in the obturator groove. The nerve to the adductor magnus 

 is given off as the obturator nerve passes through the substance of the muscle. 



(2) An articular terminal branch is supplied to the posterior aspect of the knee-joint. 



NERVUS FEMORALIS. 



The femoral nerve (O.T. anterior crural) is the large nerve for the muscles 

 and skin of the front of the thigh. It arises in the substance of the psoas major 

 muscle, from the back of the second, third, and fourth lumbar nerves, posterior to 

 the obturator nerve. Passing obliquely through the psoas major muscle, it emerges 

 from its lateral border in the pelvis major (Fig. 625, p. 721). Passing downwards 

 in the groove between the psoas and iliacus, it enters the thigh beneath the inguinal 

 ligament, lateral to the femoral sheath and femoral vessels. In the femoral triangle 

 it breaks up into a large number of branches, among which the lateral circumflex 

 artery of the thigh passes in a lateral direction. 



The branches of the femoral nerve, which are (1) muscular, (2) articular, and 



(3) cutaneous, arise in the following way : 



In the abdomen a muscular branch arises from the lateral aspect of the nerve 

 and enters the iliacus muscle. 



In the femoral triangle the terminal muscular, articular, and cutaneous branches 

 arise in the form of a large bundle of nerves. 



1. Rami Musculares. The muscular branches supply the pectineus, sartorius, 

 and quadriceps. The nerve to the pectineus arises close to the inguinal ligament, 

 and, coursing obliquely distally and medially behind the femoral vessels, enters the 

 muscle at its lateral border. It is not infrequently double. It sometimes gives off 

 a fine communicating branch to the anterior part of the obturator nerve. The 

 nerves to the sartorius are in two sets : a lateral, short set of nerves, associated with 

 the lateral part of the intermediate cutaneous nerve, which supply the proximal 

 part of the muscle ; and a medial, longer set, which are associated with the medial 

 part of the intermediate cutaneous nerve, and enter the middle of the muscle. 

 The parts of the quadriceps are supplied by several branches. The vastus lateralis 

 and rectus femoris are supplied on their deep surface by separate nerves which are 

 accompanied by branches of the lateral circumflex artery of the thigh. The vastus 

 intermedius muscle is supplied superficially by a nerve which passes through the 

 muscle, and innervates also the muscle of the knee-joint (subcrureus). It also 

 receives fibres from one of the nerves to the vastus medialis. The vastus medialis 

 muscle is supplied by two nerves : a proximal trunk, which supplies the proximal 

 part of the muscle, and sends fibres to the vastus intermedius as well ; and a distal 

 trunk, which descends on the lateral side of the femoral artery along with the 

 saphenous nerve, and passing beneath the sartorius, over or under the aponeurotic 

 covering of the adductor canal, enters the medial side of the muscle. This nerve 

 gives off a small branch which enters the medullary canal of the femur. 



2. The articular branches supply the hip and knee-joints. The articular branch 

 to the hip-joint arises from the nerve to the rectus femoris, and is accompanied by 

 branches from the lateral circumflex artery of the thigh. The articular branches 

 to the knee-joint are four in number. Three of them arise from the nerves to the 

 vastus lateralis, vastus intermedius, and vastus medialis, which, after the muscular 

 nerves are given off, are continued downwards to the knee-joint along the front of 

 the femur. A fourth articular branch arises (sometimes) from the saphenous nerve. 



3. Rami Cutanei Anteriores. The cutaneous branches are the intermediate 

 and medial cutaneous, and the saphenous nerves (Fig. 627). 



The intermediate cutaneous nerve arises in two parts, a lateral and a medial 

 branch, in the proximal part of the femoral triangle. The two branches descend 

 vertically and become cutaneous by piercing the fascia lata over the proximal third 

 of the sartorius muscle. They carry muscular branches to the sartorius, and the 

 lateral branch in many cases pierces the muscle. These two nerves supply the skin 

 of the distal three-fourths of the front of the thigh, between the lateral cutaneous 

 nerve of the thigh laterally and the medial cutaneous on the medial side. They 



