86 



MUSCLES OF THE FORE-ARM. 



Fig. 67. 



and from the interosseous ligament. Insertion, the tendons are four in 

 number, which, passing through the perforations in the tendons of 

 the flexor sublimus, are inserted into the third phalanges of the fingers. 

 Flexor longus pollicis.^ — Origin, from the internal condyle of 

 the humerus, and the middle two-thirds of the radius, and a part of 

 the interosseous ligament, hi&ertion, into the base of the second 

 phalanx of the thumb. (Fig. 66.) 



Pronator quadratus.^ — Origin, from the 

 inner surface of the ulna, near its lower ex- 

 tremity. Insertion, into the corresponding 

 surface of the radius. Use; it rotates the 

 radius inwards. 



Supinator radii longus.^^ (Fig. 67.) — 

 Origin, from the ridge leading to the ex- 

 ternal condyle of the humerus. Insertion 

 into a ridge of the radius just above its styloid 

 process.' Use ; it rotates the radius outwards. 

 Extensor carpi radialis longus J' — (Fig. 

 ^^.) Origin, From the ridge of the external 

 condyle of the humerus. Insertion, into the 

 posterior part of the base of the metacarpal 

 bone of the forefinger. Use; it extends the 

 hand. 



Extensar carpi radialis bi'evis.^ — Origin, 

 from the external condyle of the humerus, 

 and from the external lateral ligament. In- 

 sertion, into the posterior part of the base of 

 the metacarpal bone of the middle finger. 

 Use; as the last. 



Extensor carpi ulnaris,^^ — Origin^ from 

 the external condyle an,d the brachial fascia. 

 hisertion, into the base of the nrjetacarpal 

 bone of the little finger. Use; as the last. 



Extensor digitarum cominunis.^ — Origin^ 

 from the external condyle. Insertiq^i, by 

 four tendons which are connected by slips 

 previous to their being spread out, into a 

 membranous insertion, into all the phalangps 

 of the fingers. Use; it extends the joints of the fingers. 



Supinator radii brevis. — Origin, from the external condyle, and 

 from a ridge of the ulna on its posterior surface. Insertion, intp 

 the radius between its tubercle and the insertion of the pronator. 

 Use ; it rotates the radius outwards. 



Extensor ossis metacarpi pollicis manus. — -Origin, from the 

 posterior surface of the ulna, from the interosseous ligament, and a 

 part of the radius. Insertion, into the base of the metacarpal bone 

 of the thumb, and into the trapezium. 



Extensa)' minor pollicis ma?ius,^ — Origin, from the back of the 



