THE MUSCULAR SYSTEM 39 



part in this mechanism. The muscle is long 

 and triangular, and lies on the medial side of 

 the thigh practically parallel to the femur. 

 Its origin is from the projection of the hip- 

 bone immediately in front of the acetabulum. 

 A thin tendon crosses the front of the knee- 

 joint obliquely, just distal to the patella, and 

 thus gains the lateral side of the head of the 

 tibia, where it joins the flexor muscle of the 

 second and third digits. 



Since the ambiens muscle is connected with 

 two digits only, it seems obvious that it can- 

 not constitute the only factor in the perch- 

 ing mechanism. Flexion of the toes, further, 

 appears to depend greatly upon bending of the 

 intertarsal joint. It seems very probable, 

 therefore, that the passage of the flexor tendons 

 over the grooved surface at the back of the 

 distal end of the tibia is an important factor. 



