ANATOMY IN A NUTSHELL. 



Origin. (1) Upper three-fourths of shaft of ulna, anterior and inner sur- 

 faces; (2) depression ob inner side of coronoid process; (3) by aponeurosis 

 from upper three-fourths of posterior border of ulna; and (4) ulnar half of in- 

 terosseous membrane. (Plate XXV.) 



Insertion. Bases of last phalanges. (Plate XXVII.) 



\. noN. Flexes phalanges. 



\ii;\i Supply. Eighth cervical and first dorsal through ulnar, and the 

 anterior interosseous branch of median. 



Blood Si ppli . Ulnar artery. 



Flexor Longus pollicis. — Description. — (Plate XXXI.) — This muscle is 

 situated od the radial side of the forearm, lying on the same plane as the 

 preceding . The fibers pass downward and terminate in a flattened tendon 

 which passes beneath the annular ligament and is then lodged in the interspace 

 between the outer head of the Flexor brevis pollicis and the Adductor obliqus 

 pollicis. The anterior interosseous vessels and nerve lie between this muscle 

 and the Flexor profudus digitorum. 



Origin.- Front the grooved anterior surface of the shaft of the radius, 

 from the tuberosity and oblique line to within a short distance of the Pronator 

 quadratus; also from the adjacent part of the interosseous membrane, and gen- 

 erally by a fleshy slip from the inner border of the coronoid process of ulna, or 

 from the internal condyle of the humerus. (Plate XXV.) 



Insertion.- Base of last phalanx of thumb. (Plate XXVII.) 



\« tion. Flexes thumb. 



Nerve Supply.- Eighth cervical and first dorsal through the anterior 

 interosseous branch of the median. 



Blood Supply.- Radial artery. 



Pronator quadratus.— Description. — (Plate XXXI.) — This is a small, 

 flat, quadrilateral muscle extending transversely across the front of the radius 

 and ulna, above their carpal extremities. 



Origin. (1) Oblique ridge on lower part of anterior surface of ulna; (2) 

 l"\\er fourth of anterior surface and anterior border of ulna; and (3) strong 

 aponeurosis covering inner third of muscle. (Plate XXV.) 



Insertion. (Plate XXV.)- Lower fourth of anterior surf ace and anterior 

 border of shaft of radius. 



\< I [ON. Pronates the hand. 



Nerve Supply. Eighth cervical and first dorsal through anterior 

 interosseous branch <<\' median. 



Blood Supply. Radial and ulnar arteries. 



LESSON XX. 



Supinator longus. Description. (Plate XXXII.)— The Supinator longus 

 (Brachio-radialis) is the mosl superficial muscle on the radial side of the 

 forearm; it is fleshy for the upper two-thirds of its extent, tendinous below, the 

 tendon commencing above the middle of the forearm. Its inner border, above 

 the elbow, is in relation with the musculo-spiral nerve and radial recurrent 

 artery, and in the forearm with the radial vessels and nerve. 



