210 MR. ¥. E. BEDDAED— CONTEIBUTIONS TO THE 



(29) Supinator radii Irevis. — This muscle appears to be divided into two parts: one 

 superficial and one deep. The upper part of the muscle is covered by a fascia, from 

 which some of the extensors partly arise ; it arises from the ligament of the elbow- 

 joint and from the ulna ; it passes right round the radius on to the flexor side, and is 

 inserted on to that bone as far down as the beginning of the insertion of the pronator 

 •radii teres ; the lower layer of the muscle is inserted on to the extensor side of the 

 radius. 



(30) Ewtensor ossis metacarpi pollicis. — This muscle is considerably the largest of the 

 deep extensors ; it takes origin from the radius, from the ulna, from the interosseous 

 lio-ament, and from the septum between itself and the extensor secundi internodii 

 pollicis ; the radial origin commences two and a half inches below the bend of the 

 radius, and a little in front of, and below, the attachment of the deep layer of the 

 supinator radii brevis ; the tendon of this muscle is short (two inches in length), and is 

 inserted on to the radial carpal. 



(31) Extensor secundi internodii 2>ollicis. — This is a slender muscle, arising from the 

 ulna just below the ulnar origin of the last muscle ; it also arises from the interosseous 

 ligament ; the tendon, which is long and thin, passes above the tendon of the extensores 

 carpi radialis to be inserted on to the proximal end of the last phalanx of the thumb. 



(32) Extensor indicis arises from the ulna, from the interosseous ligament, and from 

 the septum between itself and the extensor carpi ulnaris; it divides into two just 

 before the wrist, and it is inserted on to the first phalanx of the index, and on to the 

 corresponding phalanx of the third digit. 



(83) There is an extensor primi internodii pollicis, the tendon of which passes in 

 close contact with the tendon of the extensor ossis metacarpi ; it is inserted on to the 

 inner side of the base of the thumb metacarpal. 



(34) Pronator radii teres. — This muscle arises from the flexor condyle of the humerus, 

 beside the palmaris loncjus and above the other flexors ; it also arises from the radius 

 and from the septa between itself and adjacent muscles ; on the radial side, where it is 

 free, it is largely covered by glistening tendon ; on the opposite surface it is nowhere 

 free, some fibres taking origin from the flexor carpi radialis just at the end of the 

 muscle ; its insertion on to the radius, which is fleshy, measures one inch and two- 

 fifths in length, and commences immediately behind the insertion of the supinator 

 brevis. 



(35) Flexor carpi radialis arises from the flexor condyle of the humerus and from 

 the septa between itself and ihe pronator radii teres and the flexor sublimis; it becomes 

 free immediately below the insertion of the pronator radii feres ; its tendon of insertion 

 does not commence until just before the wrist ; it is inserted on to the base of the 

 second metacarpal. 



(36) Palmaris lonc/us. — This muscle is the most external and superflcial of the flexors, 

 as well as the smallest ; it is hardly more than one quarter of an inch in width at the 



