286 



DISSECTION OF THE FOREARM. 



from the outer condyle of the humerus by a tendon distinct from, and on 

 the ulnar side of the common tendon of origin of the other muscles. From 

 this origin the fibres diverge to their insertion into the outer side of the 

 olecranon, and into the impression on the upper third of the posterior sur- 

 face of the ulna. 



Fig. 88. 



CD 



bfj 



b. 



o O 



r. 



-> 



8? 

 Ou, 



Id 



X 

 u 



CO 



o 



T3 





Muscles : 



A. Supinator longus. 



B. and c. Radial extensors of the carpus, cut. 



D. Supinator brevis. 



E. Extensor ossis metacarpi pollicis. 



F. Extensor primi internodii. 

 o. Extensor secundi internodii. 

 H. Extensor indicis. 



r. Posterior annular ligament. 

 Arteries : 



a. Posterior interosseous. 

 6. Recurrent interosseous. 



c. Dorsal part of the anterior interosseous. 



d. Dorsal part of the radial. 



e. Dorsal branches to the thumb and forefinger. 

 /. Dorsal carpal arch. 



ff. Two posterior interosseous (ulnar) of the 



hand. 

 Iferves : 



2. Radial. 



3. Posterior interosseons at its origin, and 4, 



near its ending in a swelling ou the back 

 of the carpus. 



DISSECTION OF THE DEEP LATER OF MUSCLES, AND THE VESSELS AND NERVE ON THE BACK OF 

 THE FOREARM. (Illustrations of Dissections.) 



The upper fibres are nearly transverse, and are contiguous to the lowest 

 of the triceps muscle. Beneath the anconeous lie the supinator brevis 

 muscle, and the recurrent interosseous vessels. 



Action. Commonly it acts on the ulna, and assists the triceps in ex- 

 tending the elbow. 



