THE SUPERFICIAL PALMAR ARCH. 545 



with the superficial volse or princeps pollicis of the radial artery. The arch passes 

 across the palm, describing a curve, with its convexity forward, to the space 

 between the ball of the thumb and the index finger, where the above-mentioned 

 anastomosis takes place. 



Relations. The superficial palmar arch is covered by the skin, the Palmaris 

 brevis, and the palmar fascia. It lies upon the annular ligament, the Flexor brevis 

 of the little finger, the tendons of the superficial flexor of the fingers, and the 

 divisions of the median and ulnar nerves. 



PLAN OF THE RELATIONS OF THE SUPERFICIAL PALMAR ARCH. 



In front. 

 Skin. 



Palmaris brevis. 

 Palmar fascia. 



Behind. 



Annular ligament. 

 Flexor brevis of little finger. 

 Superficial flexor tendons. 

 Divisions of median and ulnar nerves. 



BRANCHES OF THE SUPERFICIAL PALMAR ARCH. 



The digital branches (Fig. 304), four in number, are given off from the con- 

 vexity of the superficial palmar arch. They supply the ulnar side of the little 

 finger and the adjoining sides of the little, ring, middle, and index fingers, the 

 radial side of the index finger and thumb being supplied from the radial artery. 

 The digital arteries at first lie superficial to the flexor tendons, but as they pass 

 forward with the digital nerves to the clefts between the fingers they lie between 

 them, and are there joined by the interosseous branches from the deep palmar 

 arch. The digital arteries on the sides of the fingers lie beneath the digital 

 nerves ; and about the middle of the last phalanx the two branches for each 

 finger form an arch, from the convexity of which branches pass to supply the 

 pulp of the finger. 



Surface Marking. The superficial palmar arch is represented by a curved line, starting 

 from the outer side of the pisiform bone and carried downward as far as the middle third of 

 the palm, and then curved outward on a level with the upper end of the cleft between the 

 thumb and index finger. 



The deep palmar arch is situated about half an inch nearer to the carpus. 

 Surgical Anatomy. Wounds of the palmar arches are of special interest, and are always 

 difficult to deal with. When the superficial arch is wounded it is generally possible, by enlarging 

 the wound if necessary, to secure the vessel and tie it ; or in cases where it is found impossible 

 to encircle the vessel with a ligature, a pair of Wells's artery clips may be applied and left on for 

 twenty-four or forty-eight hours. Wounds of the deep arch are not so easily dealt with. It may 

 be possible to secure the vessel by forcipressure forceps, which may be left on ; or, failing this, 

 the wound may be carefully plugged with gauze and an outside dressing carefully bandaged on. 

 The plug should be allowed to remain untouched for three or four days. In wounds of the deep 

 palmar arch a ligature may be applied to the bleeding points from the dprsum of the hand by 

 resection of the upper part of the third metacarpal bone. It is useless in these cases to ligate 

 one of the arteries of the forearm alone, and indeed simultaneous ligation of both radial and 

 ulnar arteries above the wrist is often unsuccessful, on account of the anastomosis carried on by 

 the carpal arches. Therefore, upon the failure of pressure to arrest hemorrhage, it is expedient 

 to apply a ligature to the brachial artery. 



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