84 



MUSCLES OF THE FORE-ARM. 



Fig. 64. 



with the ten^n of the latissimus dorsi. Use ; it rotates the hu- 

 merus inwards and draws it downwards and backwards. 



Subscapularis* (Fig. 64.) Origin^ from the whole of the costa 

 of the scapula, hisertlon^ into the lower tuberosity of the humerus. 

 Use ; it rotates the humerus inwards, and draws it downwards. 



Biceps flexor cuhiti.'^ — Origin^ by a long tendon from the superior 

 extremity of the glenoid cavity, which passes through the joint 

 and bicipital groove, and by a short head 

 from the coracoid process of the scapula. 

 Insertion, into the posterior and inferior 

 parts of the tubercle of the radius, and into 

 the brachial fascia. Use ; it flexes the 

 fore-arm. 



Coraco-brachialis.^ — Origi?i, from the 

 middle facet of the coracoid process of the 

 scapula, in common with the short head of 

 the biceps. Insertion,, into the middle of 

 the OS humeri by a rough ridge on its in- 

 ternal side. Use; it draws the arm up- 

 wards and forwards. 



Brachialis Internus.^ — Origin, from 

 the anterior and lower half of the os humeri. 

 Insertion, in front of the root of the coro- 

 noid process of the ulna. Use ; it flexes 

 the fore-arm. 



Triceps extensor cuhiti}^ — Origin, by 

 three heads ; the first or longus, is from the 

 inferior part of the glenoid cavity. The 

 second or brevis, is from a ridge from the 

 back part of the os humeri, just below its 

 head ; and the third, or brachialis externus, 

 is from the inner side of the os humeri, 

 near the bicipital groove, hisertion, into the olecranon process of 

 the ulna. Use ; it extends the fore-arm. 



Anconeus.^'^ (Fig. 67.) — Origin, from the external condyle of 

 the humerus. Insertion, into the ulna below the olecranon. Use ; 

 it extends the fore-arm. 



MUSCLES OF THE FORE-ARM. 



These are eighteen in number, eight of which are on the front of 

 the arm, and are flexors, and for the most part arise from the internal 

 condyle. The remaining ten are extensors, and arise for the most 

 part from the external condyle. 



Pronator radii teres. (Fig. 65.) — Origin, from the internal 

 condyle of the humerus, and the coronoid process of the ulna. 

 Insertion, into the middle and back portion of the radius. Use ; 

 it rotates the hand inwards. 



