1040 THE XER VE # 



The superficial palmar branch (ram us superficial is n. ulnar is} supplies the 

 Palmaris brevis and the integument on the inner side of the hand, and terminates 

 in two digital branches, which are distributed, one to the ulnar side of the little 

 finger, the other to the adjoining sides of the little and ring fingers, the latter 

 communicating with a branch from the median. The digital branches are dis- 

 tributed to the fingers in the same manner as the digital branches of the median. 



The deep palmar branch (ramus profundus n. ubiaris}, accompanied by the 

 deep branch of the ulnar artery, passes between the Abductor and Flexor brevis 

 minimi digiti muscles; it then perforates the Opponens minimi digiti and follows- 

 the course of the deep palmar arch beneath the flexor tendons. At its origin it 

 supplies the muscles of the little finger. As it crosses the deep part of the hand 

 it sends two branches to each interosseous space, one for the Dorsal and one for 

 the Palmar interosseous muscle, the branches to the Second and Third palmar 

 interossei supplying filaments to the two inner Lumbrical muscles. At its ter- 

 mination between the thumb and index finger it supplies the Adductores trans- 

 versus et obliquus pollicis and the inner head of the Flexor brevis pollicis. It also 

 sends articular filaments to the wrist-joint. 



It will be remembered that the inner part of the Flexor profundus digitorum 

 muscle is supplied by the ulnar nerve; the two inner Lumbricales, which are 

 connected with the tendons of this part of the muscle, are therefore supplied by 

 the same nerve. The outer part of the Flexor profundus is supplied by the median 

 nerve; the two outer Lumbricales, which are connected with the tendons of this 

 part of the muscle, are therefore supplied by the same nerve. Brooks states 

 that in twelve instances out of twenty-one he found that the Third lumbrical 

 received a twig from the median nerve, in addition to its branch from the ulnar. , 

 The cutaneous areas supplied by the ulnar nerve are shown in Figs. 762 and 703. 



The Musculospiral Nerve (n. radialis) (Figs. 764 and 765), the largest branch 

 of the brachial plexus, supplies the muscles of the back part of the arm and 

 forearm, and the integument of the same parts, as well as that of the back of 

 the hand (Figs. 762 and 763). It arises from the posterior cord of the brachial 

 plexus, of which it may be regarded as the continuation. Its fibres are derived 

 from the sixth, seventh, and eighth, and sometimes also from the fifth cervical 

 and first thoracic nerves. At its commencement it is placed first behind the axil- 

 lary artery and then behind the upper part of the brachial artery, passing down in 

 front of the tendons of the Latissimus dorsi and Teres major. It winds around 

 from the inner to the outer side of the humerus in the musculospiral groove with 

 the superior profunda artery, between the internal and external heads of the 

 Triceps muscle (Fig. 765). It pierces the external intermuscular septum, and 

 descends between the Brachialis anticus and Brachioradialis muscles to the front 

 of the external condyle of the humerus, where it divides into the radial and pos- 

 terior interosseous nerves. 



The branches of the musculospiral nerve are: 



Muscular. Radial. 



Cutaneous. Posterior interosseous. 



The muscular branches (rami musculares n. radialis} are derived from the nerve 

 at the inner side, back part, and outer side of the arm respectively; they supply 

 the Triceps, Anconeus, Brachioradialis, Extensor carpi radialis longior, and Bra- 

 chialis anticus muscles. The internal muscular branches supply the inner and 

 middle heads of the Triceps muscle. That to the inner head of the Triceps is 

 a long, slender filament which lies close to the ulnar nerve, as far as the lower third 

 of the arm, and is therefore frequently spoken of as the ulnar collateral branch. 

 The posterior muscular branch, of large size, arises from the nerve in the groove 

 between the Triceps muscle and the humerus. It divides into branches which 



