192 HUMAN PHYSIOLOGY 



As to size we also find a great difference. /Some are 

 very short and slender, others are long ana thick. In 

 the ear there is a muscle so small that it measures about 

 one sixth of an inch in length and weighs about a grain, 

 while in the thigh there is a muscle that measures over 

 two feet in length, and in the abdomen there is a thin, 

 flat muscle over twelve inches wide. 



A muscle consists of three parts : the beginning or 

 origin, the end or insertion, and the middle or belly. Some 

 muscles are attached to bone at both ends, some at one 

 end only, the other being fastened to cartilage, skin, or 

 to another muscle, and some are not attached to bones at 

 all. Many of the muscles taper off at one or both extremi- 

 ties into thin, strong bands of connective tissue known 

 as tendons. When the fleshy part of a muscle must be 

 far removed from its insertion, it has a very long, slen- 

 der tendon, as in the case of the muscles that move the 

 fingers and toes. The largest and strongest tendon of 

 the body extends from the bone of the heel up to the 

 two largest muscles of the calf ; this is the tendon of 

 Achilles. The longest tendon of the body extends from 

 the heel bone up to a small muscle just back of the knee. 



1. Procure the lower part of a sheep's leg with the lean meat and 

 the hoof on. Dissect out as many of the muscles as you can, tracing 

 each in both directions. Find the origin, insertion, and belly of each 

 muscle. 



2. If the parts are placed in diluted alcohol for a few days they 

 will harden somewhat and remain separate. 



134. Structure of Muscles. We are all familiar with 

 the appearance and general structure of muscles as 



