152 



DISSECTION OF THE THIGH. 



Sartorius : 



origin ; 



course over 

 the thigh ; 



insertion ; 



relations of 

 the lirst or 

 oblique 

 portion, 



of the 

 middle, 



and of the 

 lower part ; 



use, the 

 limb free, 



and fixed ; 



standing on 

 one leg. 



Divide the 

 sartorius, 



show apo- 

 neurosis, 



and dissect 

 the nerves 



The SARTORIUS (fig. 58, A), is the longest muscle in the body, 

 and extends from the pelvis to the leg. It arches over the 

 front of the thigh, passing from the outer to the inner side of the 

 limb, and lies in a hollow between the extensor on the one side, 

 and the adductors on the other. 



Its origin is tendinous from the upper anterior iliac spinous 

 process of the hip-bone, and from about half the interval between 

 this and the inferior process (fig. 47, p. 113). The fibres constitute 

 a riband-like muscle, which ends in a thin tendon below the knee, 

 and is inserted into the inner surface of the tibia (fig. 68, p. 179) 

 mainly into a slight depression by the side of the tubercle for an 

 inch and a half, but also, by its upper edge, as far back as the 

 internal lateral ligament of the knee-joint. From the lower part 

 of the tendon also is an extension into the fascia of the leg. 



The muscle is superficial throughout, and is perforated by some 

 cutaneous nerves and vessels. Its upper part is oblique, and forms 

 the outer boundary of Scarpa's triangle ; it rests on the following 

 muscles (fig. 58) ; iliacus (B), rectus (D), and adductor longus (G), as 

 well as on the anterior crural nerve and the femoral vessels. The 

 middle portion is vertical, and lies in a hollow between the vastus 

 internus (E) and the adductor muscles, as low as the opening for the 

 femoral artery ; but beyond that aperture, where it bounds the 

 popliteal space, it is placed between the vastus with the great 

 adductor in front, and the gracilis (H) with the inner hamstrings 

 behind. The femoral vessels and their accompanying nerves are 

 concealed by the middle portion of the muscle. The lower tendi- 

 nous part (I) rests on the internal lateral ligament of the knee-joint, 

 being superficial to the tendons of the gracilis and semitendinosus, 

 and separated from them by a prolongation of their synovial bursa : 

 from its upper border there is an aponeurotic expansion to join 

 that from the extensor over the knee ; and from its lower border is 

 given off another which blends with the fascia of the leg. Below 

 the tendon the long saphenous nerve appears with vessels ; and 

 piercing it is the patellar branch of the same nerve. 



Action. The tibia and femur being free to move, the muscle 

 bends the knee and hip-joints over which it passes, giving rise to 

 rotation inwards of the tibia, and outwards of the femur. 



With the limbs fixed, the two muscles will assist in bringing 

 forwards the pelvis in stooping ; and when standing on one leg the 

 muscle will help to rotate the body, so as to turn the face to the 

 opposite side. 



Dissection (fig. 59). The sartorius is to be turned aside, or 

 cut through if it is necessary, to follow the remaining part of 

 the femoral artery. 



Beneath the muscle is an apoiieurosis between the adductor and 

 extensor muscles ; this is thin above, and when it is divided the long, 

 or internal, saphenous nerve will come into view. Parallel to the 

 saphenous nerve above, but outside it, is the nerve to the vastus 

 internus muscle, which sends an offset on the surface of the vastus 

 to the knee-joint : the latter may be traced now, lest it should be 



