644 SPINAL NERVES. 



branch, which joins the dorsal digital nerve, and runs along the side of the 

 dorsum of the finger, ending in the integument over the last phalanx. At the 

 end of the finger, the digital nerve divides into a palmar and a dorsal branch ; 

 the former of which supplies the extremity of the finger, and the latter ramifies 

 round and beneath the nail. The digital nerves, as they run along the fingers, 

 are placed superficial to the digital arteries. 



The Ulnar Nerve (Fig. 352) is placed along the inner or ulnar side of the 

 upper limb, and is distributed to the muscles and integument of the forearm 

 and hand. It is smaller than the median, behind which it is placed, diverging 

 from it in its course down the arm. It arises from the inner cord of the 

 brachial plexus, in common with the inner head of the median and the internal 

 cutaneous nerve. At its commencement, it lies at the inner side of the axillary 

 artery, and holds the same relation with the brachial artery to the middle of the 

 arm. " From this point, it runs obliquely across the internal head of the Triceps, 

 pierces the internal intermuscular septum, and descends to the groove between 

 the internal condyle and olecranon, accompanied by the inferior profunda 

 artery. At the elbow, it rests upon the back of the inner condyle, and passes 

 into the forearm between the two heads of the Flexor Carpi Ulnaris. In the 

 forearm, it descends in a perfectly straight course along its ulnar side, lying 

 upon the Flexor Profundus Digitorum, its upper half being covered by the 

 Flexor Carpi Ulnaris, its lower half lying on the outer side of the muscle, 

 covered by the integument and fascia. The ulnar artery, in the upper part of 

 its course,' is separated from the ulnar nerve by a considerable interval; but in 

 the rest of its extent, the nerve lies to its inner side. At the wrist, the ulnar 

 nerve crosses the annular ligament on the outer side of the pisiform bone, a 

 little behind the ulnar artery, and immediately beyond this bone divides into 

 two branches, superficial and deep palmar. 



The branches of the ulnar nerve are: 



' Articular (elbow). 



T n /~i TIT! superficial palmar. 



In forearm-} Cutaneous. In hand 1 ^ * 



TX i f J-/CC \) Ucll iliill 



Dorsal cutaneous. 

 __ Articular (wrist). 



The articular branches distributed to the elbow-joint consist of several small 

 filaments. They arise from the nerve as it lies in the groove between the inner 

 condyle and olecranon. 



The muscular branches are two in number; one supplying the Flexor Carpi 

 Ulnaris; the other, the inner half of the Flexor Profundus Digitorum. They 

 arise from the trunk of the nerve near the elbow. 



The cutaneous branch arises from the ulnar nerve about the middle of the 

 forearm, and divides into a superficial and deep branch. 



The superficial branch (frequently absent) pierces the deep fascia near the 

 wrist, and is distributed to the integument, communicating with a branch of 

 the internal cutaneous nerve. 



The deep branch lies on the ulnar artery, which it accompanies to the hand, 

 some filaments entwining round the vessel, which end in the integument of the 

 palm, communicating with branches of the median nerve. 



The dorsal -cutaneous branch arises about two inches above the wrist; it passes 

 backwards beneath the Flexor Carpi Ulnaris, perforates the deep fascia, and 

 running .along the ulnar side of the wrist and hand, supplies the inner side 

 of the little finger, and the adjoining sides of the little and ring fingers; it also 

 sends a communicating filament to that branch of the radial nerve which sup- 

 plies the adjoining sides of the middle and ring fingers. 



The articular filaments to the wrist are also supplied by the ulnar nerve. 



The superficial palmar branch supplies the Palmaris Brevis, and the integu- 

 ment on tne inner side of the hand, and terminates in two digital branches, 



