THE WRIST AXD HAXD 



1163 



the brachio-radialis. The anterior interosseous artery runs down on the inter- 

 osseous meml)rane and passes to tlie back of the forearm h»y perforating it below. 

 The posterior interosseous lies between the su])erlicial and deej) extensors. 

 These small arteries reinforce the palmar through the carpal arches, and thus bring 

 down blood after ligature of the trunks above. 



The front of the forearm is supplied by the nmsculo-cutaneous on the outer, and 

 the internal cutaneous on the inner side; just above; the wrist the palmar cutaneous 

 branches of the median and ulnar perforate the deep fascia (fig. 725). The back 

 of the forearm is supplied by the musculo-spiral and posterior branches of the 

 musculo-cutaneous externally, and the posterior branches of the internal cutaneous 

 internally (fig. 725). The arrangement of the superficial lymphatics, shown in fig. 

 726, may be briefly described as folloAvs: — 



The lymphatics of the upper extremity are superficial and deep ; the 

 former run with the superficial veins, the latter with the dee]) vessels. As a rule, 

 there are no glands below the elbow. The majority of the lymphatics open into 

 the axillary glands, and terminate on the left side, in the thoracic duct, on the 

 right, in the right lymphatic duct. A few, accomjianying the cephalic vein, reach 

 the subclavian or infraclavicular glands, and thus communicate with the Ij'm- 

 phatics of the neck. 



Fig. 727. — Relation of the Palmae Arches to the Folds of the Palm. (Tillaux.) 



Superficial palmar arch 



Deep palmar arch 



Superflcialis voice 



Inferior fold 



Middle fold 

 Superior fold 



Radial artery 



Ulnar artery 



THE WRIST AND HAND 



Bony points. — On the inner side, the styloid process and, farther outwards, the 

 head of the ulna can be made out. On tlie outer side, the radial styloid process 

 descends about half an inch (12 mm. ) lower than that of the radius, and is somewhat 

 anterior to it. Abduction of the hand is thus less free than adduction. In Colles' 

 fracture, the line of fracture, usually transverse, crosses the radius aliout an inch 

 above the apex of the styloid jn-ocess. Between the apex of the styloid process 

 and the ball of the thuml) a bony ridge can ])e felt, with some ditlieulty, formed by 

 the tubercle of the scaphoid and the ridge of the trapezium. At a corresjionding 

 ])oint on the inner side the pisiform can l)e more readily distinguished. On the 

 front of the metacarpo-phalangeal joint of the thuml) the sesamoid bones can be 

 distinguished. 



At the back of the wrist and hand the cuneiform bone can be felt below the 

 head of the ulna; and more towards the middle line the prominence of the os 



