MUSCLES OF THE RIGHT INFERIOR LIMB 65 



42. Quadriceps femoris m.: Proximal end of femur and 

 ilium; to tibia, by ligamentum patellae. Extends the leg; 

 therefore it is comparable to the triceps brachii m. (22). The 

 quadriceps is composed of five heads, or parts (four in man and 

 cat) which practically surround the femur and, with the tensor 

 fascia latae m. (34), form the bulk of the muscular part of the 

 thigh anterior to the femur. 



42a. Vastus lateralis (v. externus) m.: Origin, greater tro- 

 chanter of femur mainly. It lies along the craniolateral side of 

 the thigh, under the fascia latae and laterad to the rectus femoris 

 m. (42b). It is the largest of the quadriceps. Method: Sepa- 

 rate the vastus from the rectus (42^) by exerting lateromediad 

 strain with two fingers on the proximocranial border of the 

 vastus lateralis. Be careful not to transect the rectus femoris 

 (42b) or the vastus intermedins (426^) with the vastus lateralis. 



42b. Rectus femoris m.: Origin, superior anterior spine 

 and ventral border of ilium mainly. The rectus is a long cylin- 

 droid muscle which is intimately covered by the cranial border 

 of the vastus lateralis m. Transect. 



42c. Vastus medialis m. : Neck of femur to fascia at knee. 

 The vastus mediaUs lies caudad to the rectus femoris (42^), 

 craniad to the femoral artery (18) and laterad to the gracilis 

 m. (38). 



42 J. Vastus intermedius m.: Greater trochanter; to patella. 

 This triangular muscle lies on the craniolateral side of the femur 

 and crureus muscle (42^) with the apex of the triangle directed 

 toward the rectus m. {42b). 



426. Crureus m. (second head of vastus intermedius) : Dis- 

 tal four-fifths of cranial surface of femur; to deep fascia of knee. 



B. MUSCLES OF THE CRUS AND FOOT 



(Nos. 43-50^; Fig. 22) 



43. Gastrocnemius m.: Caput laterale, condyles of lateral 

 side of tibia and femur; caput mediale, condyle of medial side 

 of femur and sesamoid bone. Extends foot. This muscle 



