MUSCLES OF THE FORE EXTREMITY 329 



Insertion. Into the inner tuberosity on the head of the humerus. A 

 small synovial bursa is interposed between the tendon and the bone. 



Action. To adduct or draw the shoulder towards the body. 



Teres Major. A narrow muscle tapering towards the extremities, 

 and situated on the internal face of the shoulder. 



Origin. From the posterior or dorsal angle of the scapula, and from 

 the fascia underlying the subscapularis in front of it. 



Insertion. With the latissimus dorsi, into a small tubercle on the 

 inner surface of the humerus. 



Action. To flex the humerus on the shoulder and rotate it inwards. 



Coraco-Humeralis. A short muscle situated on the upper aspect of 

 the humerus or upper arm-bone. 



Origin. From a small tubercle on the inner side of the lower extremity 

 of the scapula. 



Insertion. By two divisions, one into the inner surface and the other 

 into the front of the humerus. 



Action. To rotate the arm-bone inward and adduct the shoulder. 



Scapulo-Humeralis Gracilis. A very small slender muscle situated 

 at the back of the shoulder-joint. 



Origin. From the lower part of the scapula behind, immediately above 

 the articular cavity. 



Insertion. Into the posterior part of the humerus just below its head, 

 and into the capsular ligament of the joint. 



Action. It prevents the capsular ligament of the shoulder- joint from 

 insinuating itself between the two bones. 



MUSCLES OF THE ARM 



Flexor Brachii (Biceps of Man). A long, round muscle with tapering 

 ends, largely intersected with bands of tendinous tissue. 



Origin. From a bony projection (coracoid process) at the lower and 

 front part of the blade-bone. 



Insertion. To a roughened bony eminence on the inner and upper 

 part of the radius or lower arm, and by a band of fibrous tissue to the 

 ensheathing fascia of the arm. The tendon of this muscle passes over the 

 front of the shoulder-joint and then over the " bicipital groove " on the 

 summit of the humerus. 



Between the tendon and the groove there is a large synovial bursa to 

 facilitate the play of the one over the other. 



Action. It flexes the fore-arm on the humerus, and by tightening up 

 the investing fascia gives support to the muscles in this region. 



