THE MUSCULAR SYSTEM 45 



SUPERFICIAL MUSCLES OF THE HIND LEG 



Biceps Femoris Muscle. This muscle has three portions, 

 or heads — the anterior, posterior, and accessory. The 

 origin of the anterior head is the last sacral and the first 

 caudal vertebra. The posterior and accessory heads origi- 

 nate at the sciatic tuber of the ischium. All three are 

 inserted by an extensive fascia into the distal end of the 

 femur and the proximal two-thirds of the tibia. 



Glutaeiis Maximus Muscle. This triangular muscle 

 originates by fascia from the dorsal border of the ilium, 

 from the last three sacral vertebrae, and the first caudal 

 vertebra. It is inseparably united anteriorly with the ten- 

 sor fasciae latae muscle. Its origin is covered posteriorly 

 by the anterior head of the biceps femoris. Insertion, the 

 third trochanter of the femur. 



Tensor Fasciae Latae Muscle. Origin, iliac crest. Inser- 

 tion, fascia lata of the thigh. This muscle is exposed 

 antero-ventrad to the glutaeus maximus. 



Semitendinosus Muscle. Origin, the posterior part of 

 the sciatic tuber. Insertion, by a tendon on the tuberosity 

 of the tibia. It joins the tibia from the medial side. It 

 passes from its dorsal origin down around the posterior 

 side of the thigh on to the medial surface of the shank. 

 Action, flexes and rotates the shank. 



Exercise XI. Outline the whole body of the rat as seen in the 

 lateral view, and in this outline draw and label the muscles visible 

 after the removal of the cutaneous maximus and platysma muscles. 



MUSCLES ON THE VENTRAL SIDE OF THE HEAD, 

 NECK, THORAX, AND ABDOMEN 



Place the skinned animal on its back, then dissect and 

 identify the following muscles. 

 Digastricws Mtcscle. This muscle lies between the mas- 



