SPINAL NERVES. 



703 



anterior part of the knee and leg, viz. the in- 

 fer lift I saphaenus. 



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 before 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 coming from the internal sa- 

 phasnus. 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 saphaenus itself, and also its 

 accessory branch. 



77/e accessory saphcenus nerve ( Cruveilhier) 

 takes its origin from the internal cutaneous ; 

 from the anterior crural in company with the 

 latter ; or from the trunk of the saphaenus it- 

 self. It soon divides into a superficial internal, 

 branch, which passes 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 saphaena 

 vein, which it accompanies as far as the knee- 

 joint, in which situation it communicates witli 

 the internal saphaenus 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 saphaenus 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 neive of the sapheena vein. The 

 accessory saphaenus is subject to considerable 

 variation, both as to size and origin. 



The middle cutaneous nerve 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 saphcenus. 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 cribriform 

 fascia to the saphaena vein, along which they 

 pass in a tortuous manner till lost by com- 

 municating with the internal branch of the 

 accessory saphaenus, 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 saphaenus. 



The branches to the pectineeus are directed 

 inwards behind the femoral vessels, and in 

 their course to this muscle generally send a 

 few filaments to the psoas. 



The deep-sealed muscular branches arise ex- 

 ternal to the internal saphaenus nerve, and 

 behind the superficial already described : and 

 are from within outwards : Branches for the 

 vastus interims and cruraeus : branch for the 

 rectus : and branches for the vastus externus, 

 which are the deepest of all. 



The branch for the vastus internus (short 

 saphaenus), taking its origin in close contact 

 with the internal saphaenus, 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 saphsenus ; 

 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 crurams, 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- 

 cruraeus) to the periosteum and upper part of 

 the synovial capsule. 



The branch for 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. 



The branch for the vast us c.i-l<Titus frequently 

 arising in company with that for the rectus, 

 is directed downwards and outwards between 



