10 MR. E. J. SIDEBOTHAM ON THE [Jan. 21), 



Tendon grooved, tendon of palmaiis longus first lying in it, and 

 then inserted into it. Common tendon divides into five, which 

 are inserted into bases of terminal phalanges of fingers. 



Lumbricales three in number: — I. Arising from second and 

 third flexor tendons, inserted into outer side of medius. 2. Arising 

 from third and fourth flexor tendons, inserted into outer side of 

 annularis. 3. Arising from ulnar side of fourth tendon, inserted 

 into outer side of minimus. 



Flexor digitorum sufjliniis. — Arises from lower third of flexor 

 profundus as a small muscular belly. It gives off three tendons, 

 each of which splits opposite first inter-phalangeal joint, and allows 

 tendon of deep flexor to pass through. The spht tendons ilien 

 rejoin, and are inserted into upper third of second phalanges of 

 index, medius, and annularis. 



Pronator radii teres. — Arises from internal condyle of humerus, 

 and is inserted into outer border of radius at its middle third. 



Pronator quadratus consists of thin fibres extending between 

 anterior surfaces of radius and ulna in their lower half. 



Supinator longus. — A well-developed muscle, arising from upper 

 part of external supracondyloid ridge of humerus, anterior to 

 extensor carpi radialis longior, with which it is closely united at its 

 origin. At its lower third it ends in a thin tendon, which, becoming 

 closely applied to external lateral ligament, is inserted into dorsal 

 and outer surfaces of wrist. 



Extensor carpi radialis longior. — Arises from external supra- 

 condyloid ridge of humerus and external condyle, being united with 

 following muscle for about an inch. Tendon inserted into outer 

 side of metacarpal of index at its proximal third. 



Extensor carpi radialis brevior. — Arises in close connection with 

 ])receding muscle, inserted into outer side of metacarpal of medius 

 at its proximal third. 



Extensor digitorum communis. — A somewhat small muscle, arising 

 from external condyle of humerus in common with extensor minimi 

 digiti. Tendon divides into three — one passing to dorsum of index, 

 another dividing and passing to medius, whilst the third one divides, 

 one division passing to annularis whilst the other passes to minimus. 



Extensor minimi digiti. — Thin, arising from external condyle of 

 humerus with common extensor. Its tendon divides into two, which 

 are inserted on ulnar sides of tendons from common extensor passing 

 to annularis and minimus. 



Extensor carpi ulnaris. — Arises from outer condyle of humerus, 

 inserted into inner side of wrist. 



Extensor secundi internodii pollicis. — Arises from inner side of 

 olecranon, and inner side of upper fourth of posterior surface of 

 ulna. Its tendon divides into two slips — one being inserted into base 

 of first phalanx of thumb, the other into base of first phalanx of 

 index, on radial side of common extensor. 



Extensor ossis metacaipi pollicis. — Arises from extensor surface 

 of ulna in its upper half and from upper third of radius. Tendon 

 inserted into base of metacarpal of thumb on its outer side. 



