POSTERIOR BRACHIAL GROUP. 219 



Posterior Brachial Group. 



Scapulo-ulnaris. 

 Triceps extensor brachii. 

 Anconeus. 



SCAPULO-ULNARIS. 



{Scapido-olecranius Longus.) 

 (Fig. 79. d.) 



Situated on the postero-internal aspect of the region, adhering- 

 to the caput magnum, this is a broad and flat muscle, aponeurotic 

 at its origin, with a fleshy belly, and divisible into an anterior 

 and posterior portion. 



Origin. — Aponeurotic, from the dorsal angle and posterior 

 costa of the scapula. 



Insertion: — To the inner part of the apex of the olecranon, 

 and to the antibrachial fascia. 



Relation. — Externally with the caput magnum ; anteriorly 

 with the caput medium ; internally with the pectoralis magnus ; 

 superiorly with the latissimus dorsi. 



Action. — To flex the shoulder joint, extend the elbow joint, 

 and tense the antibrachial fascia. 



TRICEPS EXTENSOR BRACHII. 



{Triceps Brachii.) 



(Fig. 78. d, e.) 



A very large and powerful muscle, occupying the space between 

 the posterior border of the scapula, the humerus, and the 

 olecranon. It consists of three parts, which have different origins, 

 but a common insertion to the olecranon process. We describe 

 them as if they were separate muscles, under their respective 

 names : — 



Caput magnum. 



Caput medium. 



Caput parvum. 



