224 ANATOMY OF THE LOWER EXTREMITY. 



upper part, to divide into two layers, between which lies 

 the tensor vaginae femoris. 



The TENSOR VAGINAE FEMORIS is a short and thick mus- 

 cle, arising from the anterior superior spinous process and 

 a portion of the crest of the ilium ; it is inserted into tin 

 fascia lata between its two laj-ers, at a point five or si: 

 inches below that of its origin. 



The fascia lata may be removed as far as the anterior border of the 

 tensor vaginae muscle, but it should not be divided transversely until 

 the vastua externus is dissected. The removal of that part of the 

 fascia in front of the thigh exposes the sartorius and rectus muscles. 

 In dissecting the sartorius it will be found advantageous to remove 

 its anterior sheath without disturbing the posterior adhesions which 

 keep the muscle in place : when this is accomplished it may be dis- 

 sected posteriorly, but it is so long a muscle that it is difficult to keep 

 it tense, or to dissect it neatly. 



The SARTORIUS MUSCLE arises from the anterior superior 

 spinous process of the ilium, and crosses the thigh obliquely 

 to the inside of the knee, where it forms a thin, flat tendon 

 which is inserted into the inner tuberosity of the tibia by 

 an aponeurotic expansion, which loses itself in the fibrous 

 tissues surrounding the knee-joint. 



In dissecting the origins of the three following muscles, they must 

 be free from all tension ; but in preparing their bellies and insertions 

 they should be made tense, and this will be accomplished by bending 

 the knee upon the thigh. The length and rlaccidity of the sartorius 

 permit its being drawn to one side, so as not to interfere with the dis- 

 section of the parts beneath. The second head of the rectus is not 

 easily seen, as it is very short; by lifting the muscle upward and 

 inward it may be isolated from the surrounding parts, and brought 

 into view. 



The RECTUS FEMORIS MUSCLE lies upon the front of the 

 femur, forming a beautiful muscular mass, the fibres of 

 which radiate from a central longitudinal line in a bipenni- 

 form manner. It arises b}^ two tendinous heads, one from 

 the anterior inferior spinous process of the ilium, just below 

 the origin of the sartorius ; the other from the upper surface 

 of the acetabulum ; it is inserted by a broad flat tendon 

 into the upper border of the patella. 



The VASTUS EXTERNUS MUSCLE is partly covered in by 

 the fascia lata into which the tensor vaginae femoris is in- 

 serted ; it forms the bulk of the outer, fleshy part of the 

 thigh ; it arises from the base of the trochanter major, and 

 from the whole length of the linea aspera, and is inserted 



