62 THE. MUSCULAR SYSTEM OF THE FROG 



1. Muscles of the thigb. 



Remove the skin from one of the legs of the frog, awl clean the 

 m/mde8 fi/rst of the preaxial and then of the postaxial surfaces. 



a. Superficial muscles of the preaxial (apparent ventral) 



surface of the thigh. 



— I — i. The sartorius is a long narrow muscular band which 



crosses the thigh somewhat obliquely from the 



ou ter to th e inner side. It arises from theQha^ 



■-fymphysIsTpelow the acetabultim, and is inserted 



' iiilu Ihe i B ner side of the head of the K^l 



-4— ii. The adductor magnus is a large muscle lying along 

 the inner border of the sartorius, but passing 

 h p.neath it at if ,! ^ distal end. It arises from the 

 Cpu bic and ischial SYmphyse| > and passes under 

 the sar tori^ to be inserted into the distal third 

 of the tfemuS 



— iii. The adductor longus is a long narrow muscle lying 

 along the outer side of the a,dductor, magnus, 

 and of ten-~completely hidden by the sartorius : 

 it arises from the iliac symphysis beieath the 

 sartorius, and unites a little way be^yond the 

 middle of the thigh with the adductor magnus. 



iv. The rectus intemus major is a large muscle lying 

 along the inner side of /the* adductor magnus 

 and of the sartorius. Ii/ arises from the ischial 

 symphysis and is inserted into the head of the 

 tibia. j 



V. The rectus intemus mii^or is a nan'ow flat band of 

 muscle running along the inner ,,or flexor margin 

 of the thigh : it arisefe from a tendinous expansion 

 connected with the ischial ^rmphy^, and is 

 inserted into the inner side/ of the tibia, just 

 below its head. 



b. Superficial muscles of the Extensor surface of the thigh. 



j. The triceps ^ gteniq ^ femoris, the great extensor 

 mtiscle of the thigh, arises by three distinct 

 origins, which will be described separately, and 

 is inserted into the pB^just below its head; 



