DISSECTION OF THE POSTERIOR LIMB. 69 



■ passage of the common tendon, and becomes inserted in common with 

 that tendon.* 



Action. — The same as the two preceding muscles. 



Z>ireci!iows.— The tensor vaginse femoris and the gluteus internus 

 should now be out away, care being taken not to injure the capsular 

 hgament, on which the latter muscle rests. The rectus femoris, vastus 

 externus, and rectus parvus are then to be dissected. The last- 

 mentioned muscle will be found by dissecting deeply into the upper part 

 of the interstice between the other two muscles, and at the same point 

 the iliaco-femoral artery will be found. 



The Iliaco-pbmoral Artery is one of the terminal branches of the 

 internal iliac (Plate 48). It comes out between the iliacus and the 

 shaft of the ilium, and penetrates between the rectus femoris and 

 the vastus extei-nus. 



The Kbctus Femoris (Plate 18) arises by two heads — one from each 

 of the depressions on the shaft of the ilium, above and in front of the 

 cotyloid cavity. The central portion of the muscle is thick and fleshy, 

 and rests in a groove formed by the twoVasti, with which it is confounded 

 at its lower extremity. It is inserted into the anterior face of the 

 patella. 



Action. — To flex the hip-joint and extend the stifle. 



The Vastus Externus (Plate 18) arises from the outer surface of the 

 femur, and from the outer half of the anterior surface of the same bone. 

 Its fibres become inserted along with the rectus femoris into the patella. 



Action. — To extend the stifle. 



The Rectus Parvus (fig. 2) is very slender when compared with 

 the muscles between which it is placed, being about the thickness of 

 a human finger. It arises from the ilium, external to the pit from 

 which the outer head of the rectus femoris takes origin. Passing in 

 front of the capsular ligament of the hip-joint, to which it adheres, 

 it insinuates itself between the two vasti muscles, and is inserted 

 into the anterior surface of the femur. 



Action. — The muscle is of too slender a size to exert any appreci- 

 able flexor action on the hip-joint, and probably its function is to raise 

 the capsular ligament during flexion of the joint. (See footnote, 

 page 62.) 



Directions. — The dissector is now in a position to detach the limb 

 from the trunk, and this should be done by cutting through the bone 

 and soft structures, below the level of the internal trochanter. It is 

 necessary to make the section at this point, in order to leave the hip- 

 joint and the common insertion of the iliacus and psoas magnus intact 

 for examination by the dissector of the abdomen and pelvis. The limb 



* In man this muscle consists of two separate slips, and from this disposition it is named. I do 

 not hesitate to give it the same designation here, although I have never found it double as it is 

 usually described. 



