CHAP, v.] THE CATS 3IUSCLf:S. 149 



process. At its upper part this muscle is closely connected with the 

 tendon of insertion of the deltoid. 



The coraco-brachialis draws the arm a little forwards and upwards, 

 the biceps and brachialis anticus flex the elbow-joint, which is 

 extended by the following muscle. 



The triceps. — This is an enormous muscle, consisting of five parts. 

 (1.) The first part (Fig. 80, Tr^), takes origin from the summit of 

 the outer, posterior part of the humerus, within the tendon of 

 insertion of the teres minor. Passing downwards, it blends 

 with the second part a little above the elbow. 

 (2.) The second and largest part arises by a strong, broad tendon 

 from the lower half of the axillary border of the scapula, 

 between the subscapularis and teres minor ; after receiving the 

 accession of the first part it is inserted by a strong tendon into 

 the end of the olecranon. 

 (3.) The third part takes origin from the upper part of the inner 

 side of the shaft of the humerus, mainly below, but partly 

 overlapped by, the tendon common to the teres major and latissi- 

 mus dorsi. Passing downwards it soon blends with the fourth 

 part. 

 (4.) The fourth part takes origin from the whole upper surface of 

 the humerus just below its head, — from the origin of the first 

 part of the triceps externally, to the insertion of the coraco- 

 brachialis internally. Passing downwards it receives the 

 accession of the third part and is inserted into the olecranon. 

 (5.) The fifth and much smallest part arises from just above the 

 internal condyloid foramen, and from the bridge of bone 

 bounding that foramen, down to the internal condyle. Passing 

 obHquely backwards (Fig. 81, f^) it is inserted into the inner 

 margin of the olecranon. 

 The anconeus is much larger than the fifth head of the triceps. 

 It arises from a triangular surface (with the apex upwards,) on the 

 lower half of the shaft of the humerus (especially towards the outer 

 side of that bone,) its origin extending to the margins of the 

 olecranal fossa and right down to the external condyle. The 

 muscle lies between the first and third parts of the triceps, and is 

 inserted into the whole of the fossa on the outside of the olecranon. 

 The muscles of the fore-arm consist of pronators and supinators, 

 flexors and extensors, and their names sufficiently indicate their actions. 

 The pronator teres arises from the inner condyle and passes down 

 obliquely to its insertion into about the middle third of the front of 

 the radius. 



The flexor car^n radialis is long and narrow. It arises from the 

 internal condyle of the humerus in common with the head of the 

 flexor profundus, and is inserted into the proximal end of the 

 palmar surface of the second metacarpal. 



The pahnaris longus arises from the internal condyle, and passmg 

 down becomes tendinous at the wrist, and ends in an aponeurotic 

 expansion (called the palmar fascia), which exhibits tendinous 



