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supraspinatus only abducts. The infraspinatus rotates out 

 and carries the arm back when it is raised. The subscapularis 

 rotates in and carries the arm forward when it is raised. The 

 teres minor rotates the raised humerus out and depresses it. 

 All act as accessory ligaments to the joint. The teres major 

 assists the latissimus dorsi in lowering the humerus, when 

 raised, also acting as an internal rotator of the shoulder-joint. 



THE MUSCLES AND FASCLffi OF THE ARM 



The aponeurosis of the arm (deep fascia) is thin over the 

 biceps, strong over the triceps, and is attached to the humerus 

 intermuscular septa (ligamenta inter muscularia) . The external 

 intermuscular septum extends from the outer epicondyle and 

 supracondylar ridge to the deltoid insertion; it is pierced by 

 the musculospiral nerve and superior profunda artery. The 

 internal intermuscular septum extends from the inner epicondyle 

 and inner supracondylar ridge to behind the coracobrachialis; 

 it is pierced by the anastomotica magna artery. 



The internal brachial ligament of Struthers is a fibrous band 

 below the teres major insertion to the inner epicondyle; the 

 ulnar nerve and inferior profunda artery pass between this 

 band and the internal intermuscular septum. 



The Muscles of the Anterior Humeral Region 



M. Biceps Flexor Cubiti (brachii). Its short or inner head 

 rises with the coracobrachialis from the tip of the coracoid 

 process; the long head, from the upper end of the glenoid cavity 

 within the capsule by a tendon continuous on each side with 

 the glenoid ligament; these two heads form a belly in the 

 middle and lower part of the arm. The tendon of insertion is 

 slightly twisted and attached to the back part of the tuberosity 

 of the radius, separated from the forepart by a bursa. A 

 second bursa may be between the tendon and ulna. From 

 the inner side of the tendon a part branches off as an aponeurotic 

 band or bicipital fascia, p. n., and blends with the, deep fascia 

 of the forearm stretched across the brachial vessels and median 

 nerve. 



M. Coracobrachialis. Origin, tip of the coracoid between 

 the pectoralis minor and short head of the biceps, conjoined 



