712 



MUSCLES OF THE ARM. 



which is inserted into the lesser tuberosity of the humerus. 

 Between the tendon of this muscle and the neck of the 

 scapula, a large bursa communicating with the joint is 

 seen ; also another smaller one between the tendon and 

 capsular ligament. Function. To roll the arm inward and 

 downward. 



MUSCLES OF THE ARM, (Fig. 225.) 



These comprise the biceps flexor cubiti, 

 cwaco-bradiialis , brachialis anticus, tri- 

 ceps extensor cubiti, and anconeus. 



Biceps flexor cubiti. Dissection. 

 Make an incision along the middle an- 

 terior region of the humerus down to 

 the elbow-joint, which cross by a trans- 

 verse incision at the middle of the arm, 

 turn aside the integuments and fascia, 

 11 and this muscle will be exposed. It is 

 superficial and forms the swell along the 

 front part of the arm. It arises by 

 two heads ; the internal or short head 

 comes from the coracoid process in com- 

 mon with the coraco-brachialis ; the ex- 

 ternal or long head arises by a round 

 tendon from the upper part of the gle- 

 noid cavity of the scapula, goes through 

 the joint, over the head of the humerus, 

 surrounded by, but external to, the sy- 

 novial membrane, and then descends 

 through the groove between the tuberos- 

 ities of the humerus, between the tendons 



FIG. 225 represents the Muscles on the front of the Arm. 1 Clavicle. 

 2 Coracoid process. 3 Acromion process. 4 Head of the humerus. 5 Ten- 

 don of the biceps. 6 Ligamentum adscititium. 7 Insertion of pectoralis major. 

 8 Long head of the biceps. 9 Insertion of the deltoid. 10 Insertion of pec- 

 toralis minor. 11 Coraco brachialis. 12 Short head of biceps. 13 Latissi- 

 mus dorsi. 14 Triceps. 15 Body of the biceps. 16 External part of triceps. 

 17 Brachialis anticus. 18 Origin of the flexor muscles. 19 Insertion of bra- 

 chialis an ticus. 20 Tendon of the biceps. 21 Bicipital aponeurosis. 22 Flexor 

 carpi radialis. 23 Palmaris longus. 24 Supinator radii longus. 



