386 A MANUAL OF ANATOMY. 



and the posterior carpal branch of the radial. Its branches 

 are distributed to the surrounding muscles and to the wrist- 

 joint. 



The Posterior Inter osseous Nerve. Fig. 79. 



Is a branch from the musculospiral just above the exter- 

 nal (epi)condyle in the interval between the supinator longus 

 and the brachialis anticus. See page 31 8. It descends to 

 the anterior surface of the supinator brevis, through which 

 it passes to the back of the forearm, where it is found under 

 the superficial layer of muscles. As it descends it passes 

 under the deep muscles to the interosseous membrane, upon 

 which it lies, and ends just above the wrist-joint in a small 

 ganglion. 



The nerve gives off branches to all the muscles at the back 

 of the forearm and the ganglion, to the wrist and carpal 

 joints. 



The Termination of the Anterior Interosseous Artery. 



Fig. 79. 



This is found coming through the interosseous membrane 

 about an inch and a half above the wrist. It descends to 

 the back of the wrist, where it enters into an anastomosis 

 with the posterior carpal of the radial. In its course it 

 forms an anastomosis with the posterior interosseous above 

 the wrist. 



The Recurrent Interosseous Artery. Fig. 79. 



Is a branch of the common or the posterior interosseous. 

 It is found on the back of the forearm as it curves upward 

 over the supinator brevis. It runs upward between this 

 muscle and the anconeus to the back of the elbow-joint 

 between the external (epi) condyle and the olecranon pro- 

 cess, where it enters into the elbow anastomosis. 



