520 



REGIONS OF THE HAND. 



brandies to supply the pulp of the fingers. 

 When the artery arrives at the wrist, it sends 

 off two regular branches, the arteriae carpi ulna- 

 res anterior et posterior, to the fore and back 

 parts of the joint. After crossing the annular 

 ligament, it detaches also a deep communicat- 

 ing branch, which dips down between the 

 flexor brevis and abductor minimi digiti, to join 

 the deep arch from the radial. 



The radial artery, just below the styloid 

 process of the radius, passes round to the back 

 of the wrist under the two external extensors of 

 the thumb, to the cleft between the two first 

 metacarpal bones, where it again passes into 

 the palm between the heads of the first dorsal 

 interosseous, and then between the short flexor 

 and adductor of the thumb, to form with the 

 communicating branch from the ulnar the deep 

 palmar arch. In this course it lies upon the 

 capsular and external lateral ligaments, and 

 close upon the head of the first metacarpal 

 bone; it is therefore generally divided in the 

 amputation of that bone ; but it would often be 

 avoided, were the edge of the knife kept close 

 to the inner side of the bone, as it is carried 

 down to the joint. Before it curves round the 

 wrist, this artery gives off the superficialis volae, 

 a branch which runs over the annular ligament 

 to unite with thesuperficial palmar arch; also the 

 anterior carpal branch, which anastomoses with 

 the anterior interosseous and corresponding ulnar 

 branch. At the back of the carpus it detaches 

 the dorsalis carpi radialis, which inosculates 

 with the corresponding branch from the ulnar; 

 it runs beneath the extensor tendons, supplying 

 the synovial membrane and the bones of the 

 carpus ; it also anastomoses with the posterior 

 interosseous. This branch generally sends off 

 the metacarpal artery, which forms a kind of 

 posterior arch across the heads of the metacarpal 

 bones, that supplies the integuments and inter- 

 ossei muscles ; this metacarpal branch some- 

 times arises from the trunk of the radial. The 

 only remaining dorsal branches are, the arteriae 

 dorsales pollicis, in general two distinct branches, 

 but sometimes arising by a common trunk. 

 They run along the dorsum of the thumb, the 

 one on the radial, the other on its ulnar side ; 

 this last sends a branch to the index finger, the 

 dorsalis indicis. The radial artery then dips 

 deep into the palm, as before described, and 

 divides into its three terminal branches: the 

 first is the magna pollicis, which runs along the 

 ulnar side of the metacarpal bone of the thumb, 

 and at its inferior extremity divides into two 

 collateral branches, which are distributed simi- 

 larly to those of the fingers. The next branch 

 is the radialis indicis, which forms the external 

 collateral artery of that finger; it receives a 

 branch of communication from the superficial 

 palmar arch. Lastly, the arteria palmaris pro- 

 funda ; this runs deeply into the palm, generally 

 separating the flexor brevis and adductor pollicis 

 muscles. It crosses the interossei and anterior 

 part of the superior extremities of the metacarpal 

 bones ; it is covered by the deep flexor tendons 

 and lumbricales ; and opposite the fifth meta- 

 carpal bone inosculates with the communicating 

 ulnar, completing thus the deep palmar arch, 



the convexity of which is towards the fingers ; 

 and it gives four or five regular branches, which 

 supply the interossei, and at the clefts of the 

 fingers anastomose with the digital branches. 

 This arch is less oblique, and farther from the 

 fingers, than the superficial one. 



Thus we see that the disposition of the arteries 

 of the hand is peculiar, and is somewhat analo- 

 gous to that of the venous system generally, 

 viz. that they are divided into a superficial and 

 deep set. The question naturally occurs, whe- 

 ther it may not be for the same cause, viz. that 

 when pressure obstructs the superficial vessels, 

 the deep may still carry on the interrupted cir- 

 culation 1 In the hand, as we have seen, the 

 communications between the deep and super- 

 ficial arches are frequent and free, while we 

 daily experience with what violent and continued 

 pressure the circulation through the superficial 

 arch is liable to be interrupted. 



The varieties of the arteries of the hand are 

 numerous : sometimes the radial predominates, 

 at other times the ulnar, in the share they respec- 

 tively take in supplying the hand; they are 

 always in an inverse ratio; and if both are small, 

 then the artery of the mtdian nerve derived 

 from the interosseous is proportionably large. 



From the constant call for vigorous and rapid, 

 as well as sustained and powerful action, the 

 hand, with the exception of the tongue, is the 

 most vascular of the voluntary locomotive mem- 

 bers of the human body. The communications 

 between its arteries are so numerous and free, as, 

 in cases of simple wounds of this region, fre- 

 quently to prove a source of great embarrass- 

 ment to the surgeon, and, in unskilful hands, of 

 danger to the patient. Wounds of the integu- 

 ments of the palm often bleed profusely, and 

 are liable to secondary haraorrhage. This may 

 in some measure be accounted for by the pecu- 

 liar density of the cellular tissue and skin, and 

 its intimate connection with the subjacent fascia, 

 which, as well as the numerous branches given 

 off from the divided vessels, prevent their re- 

 traction, nor can a coagulum easily form around 

 them ; they are not generally vessels that require 

 a ligature, (excepting in cases similar to one 

 related by M. Velpeau, where the arteries of 

 the hand were in a varicose state, and of an 

 enormous size,) but where ordinary means fail, 

 plugging the wound, the continued application 

 of cold, and a lightish bandage up to the 

 shoulder, in order to moderate the circulation 

 in the whole limb, will usually stop even very 

 severe bleedings. If these means should not 

 succeed, and no large divided vessels can be 

 seen in the wound, the surgeon must tie one or 

 even both arteries above the wrist. The inos- 

 culations with the interosseous will sometimes 

 even then allow the bleeding to continue, espe- 

 cially in cases where the median branch is 

 large, or helps to form the arch ; but pressure 

 and cold will then soon stop the remaining 

 hemorrhage. 



Veins. The deep ones accompany their 

 arteries ; the superficial veins are very few on 

 the palm. 



The lymphatics accompany the veins. 



T/ie. nerves of this region are superficial and 



