DISSECTION OF THE ARM. 



origin from scapula. 

 the scapula ; 



insertion 

 into radius 



The short head is the innermost, and arises from the 

 ^ Q f ^ Q coracoid process in common with the coraco-brachialis 

 muscle (fig. 10, p. 29) ; and the long head is attached just above the 

 glenoid fossa of the scapula, within the capsule of the shoulder-joint 

 and is connected with the glenoid ligament on either side of the fossa. 

 Muscular fibres spring from each tendinous head, and meet to form 

 a fleshy belly, which is somewhat flattened from before back. 

 Inferiorly the biceps ends in a tendon, which is inserted into the 

 tuberosity of the radius (fig. 25, p. 61), having previously given off 

 a slip to the fascia in front of the elbow. 



Pectoralis major. 



Supinator longus. 



Ext. carpi radialis longior. 

 Common origin of extensors. 



Supraspinatus. 

 Subscapularis. 



Latissimus dorsi. 

 Teres major. 



Inner head of triceps. 



Coraco bracliialis. 



Pronator teres. 

 Common origin of flexors. 



FIG. 17. THE HUMERUS FROM THE FRONT. 



parts The muscle is superficial except at the extremities. At the 



upper part it is concealed by the pectoralis major and deltoid 

 muscles ; and at the lower end the tendon dips into the hollow in 



and beneath front of the elbow. Beneath the biceps are the musculo-cutaneous 

 nerve, the upper part of the humerus, and the brachialis anticus 



inner border muscle. Its inner border is the guide to the brachial artery below 



thfPartery ; the middle of the humerus, but above that spot the coraco-brachialis 

 muscle intervenes between them. The connection of the long head 

 of the biceps with the shoulder-joint and the insertion of the muscle 

 into the radius will be afterwards learnt. 



radius Action. It bends the elbow-joint, and acts powerfully in 



