8 THE HUMAN MECHANISM 



3. Muscles and deeper connective tissues. 1 The subcu- 

 taneous connective tissue sometimes connects or binds the 

 skin directly to bone, as in parts of the head ; usually, how- 

 ever, in the neck, trunk, and limbs the underlying tissue is 

 the red flesh, or muscle, familiar to us as " lean of meat." 

 If the skin be removed from the forearm, it at once becomes 

 evident that this mass of meat or flesh is composed of a 

 number of muscles which may be separated from one an- 

 other more or less completely. In doing this it will be found 

 that the muscles are held together by connective tissue in 

 most respects quite similar to that immediately under the 

 skin. Further dissection will show that one or another form 

 of this tissue is the means of binding other organs together ; 

 thus the muscles are joined to the bones by a very dense, 

 compact, and strong form known as tendon:, the bones are 

 united by a somewhat similar r.rm known as ligament; and 

 so on. The physical characters of the tissue differ widely, 

 according to its situation and the use subserved; but one 

 form shades more or less into another, and we have no diffi- 

 culty in recognizing the general similarity which leads us to 

 group them all together in one class. 



4. Muscles attached to bones. When a muscle is carefully 

 dissected away from neighboring muscles and other organs, 

 it is almost always found that it is attached to one and 

 usually to two bones; this union is frequently made by 

 means of a tendon, as in the case of the large muscle of the 

 calf of the leg, which is attached at one end to the bone 

 of the thigh and at the other to that of the heel. A good 

 example of the direct attachment of muscles to bones is 

 furnished by those muscles which lie between the ribs (see 



1 The general appearance and arrangement of muscles, their attachment 

 by means of tendons to bones, and the action of tendons on bones can be 

 beautifully shown by a dissection of the leg of a chicken. The difference 

 between trunk and limbs in the matter of the body cavity may also be 

 readily demonstrated on the same animal. 



