Wrist and Hand. 



93 



(Fig. 4.) 

 Synovial Sheaths of Palm and Fingers. 



anterior annular ligament. 

 (Fig. 4.). These flexor 

 sheaths for the fingers line 

 the interior of the vaginal 

 or fibrous channels and are 

 reflected from the walls of 

 these channels to the tendons 

 on their entrance into them, 

 as well as, ,at their termina- 

 tions at the bases of the last 

 phalanges. 



(6) The deep palmar arch 

 is situated under these flexor 

 tendons and is the continua- 

 tion of the radial artery. This 

 artery leaves the front of 

 the wrist immediately be- 

 low the styloid process of the radius and runs outwards 

 over the scaphoid and trapezium, and beneath the exten- 

 sor muscles of the thumb, to the cleft between the first and 

 second metacarpal bones. It then enters the palm, and, as 

 the deep palmar arch, passes in a direction, slightly curved, 

 across the bases of the metacarpal bones to terminate near 

 the base of the metacarpal bone of the little finger. Un- 

 derneath the deep palmar arch and separated from it by a 

 layer of deep fascia, are (7) the palmar inter ossei 

 muscles, which, arising from the sides of the metacarpal 

 bones, are inserted into the borders of the phalanges and 

 into the expansions of the extensor communis tendons be- 

 hind, while (8) the lumbricales are inserted into the ex- 

 pansions only, and not into the sides of the phalanges. 

 The remaining muscles of the palm are those for the 

 thumb and the little finger. 



Dorsal Surface. The deep fascia is thickened and at- 



