110 



ANATOMY FOR NURSES 



[Chap. VII 



muscles we have mentioned as covering the back, the trapezius and 

 latissimus dorsi, and the pectoral muscles covering the front of the 

 chest, are the chief. 



The muscles of the extremities are arranged in antagonistic 

 groups, the action of one group opposing the action of the other. 

 The movements of which the extremities are capable are flexion 

 and extension, abduction and adduction, supination and prona- 

 tion, circumduction and rotation. (See page 87.) 



Functionally we might group the muscles of the upper extremi- 

 ties as follows. 



Deltoid. — The deltoid is a coarse, triangular muscle covering 

 the top of the shoulder. It arises from the clavicle, acromion 

 process, and spine of the scapula, extends downw^ard, and is 

 inserted into the middle of the shaft of the humerus, on the outer 

 side. (See Fig. 81.) 



Action. — It abducts — raises the arm from the side so as to 

 bring it at right angles to the trunk. This action is opposed 



