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-l)one. 



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. 



