PRACTICAL CONSIDERATIONS : WRIST AND HAND. 



615 



Bursa surrounding ten- 

 don of flexor longus 

 pollicis 



One of the most common and most serious of the sequelae of fracture of the 

 lower end of the radius is stiffness of the wrist and fingers from adhesions of these 

 extensor tendons and their sheaths to the bone, to each other, and to the surrounding 

 structures. 



It is important to remember, as Treves has pointed out, that ' ' the tendons do 

 not lie free within the sac, but are bound to it by folds of synovial membrane in 

 much the same way as the bowel is bound to the abdominal parietes by its mesen- 

 tery (Fig. 492). These folds may be ruptured in severe sprains, when the nutrient 

 vessels for the tendon, which are contained in them, may be torn. Rupture is fol- 

 lowed by effusion into the sac. These folds are almost absent within the digital sheaths, 

 the slight ligamenta 



longa and brevia, near F^"^- 592- 



the insertion of the 

 tendons, being the sole 

 representatives. Sy- 

 novial sacs are lined by 

 endothelium, and have 

 extremely free com- 

 munication with the 

 lymphatic vessels of 

 the part. Hence the 

 free absorption of in- 

 fective matter from 

 such cavities." 



The arrangement 

 of tlie synovial sheaths 

 beneath the anterior 

 annular ligament is 

 of great practical im- 

 portance (Fig. 592). 

 There are two sacs, 

 one for the tendons of 

 the superficial and the 

 deep flexors ; one for 

 the long flexor of the 

 thumb. They extend 

 upward to about two 

 finger-breadths above 

 the annular ligament. 

 Downward, that for 

 the thumb extends to 

 the insertion of the 

 tendon in the terminal 

 phalanx ; the divertic- 

 ula for the index, mid- 

 dle, and ring fingers 

 end about the mid- 



Digital sheaths- 

 01 long flexor 

 tendons 



Anterior annu- 

 lar ligament 

 (cut) 



Palmar bursa sur- 

 rounding long 

 flexor tendons 



Prolongation 

 into tendon 

 sheath of lit- 

 tle finger 



die of the metacarpal 



Dissection of palmar surface of right hand, showing artificially distended sheaths 



bones ; that for the lit- " of flexor tendons. 



tie finger accompanies 



the tendon of the deep flexor to its insertion in the last phalanx. The synovial 



sheaths for the digital portions of the flexors for the index, middle, and ring fingers 



extend upward only to about the necks of the corresponding metacarpal bones. They 



are thus separated by an interval of from half an inch to an inch from the synovial 



sac, extending up under the annular ligament to the forearm (Fig. 592). 



It results from this that infections (felons, wounds, etc.) of the thumb or little 

 finger are especially apt to extend upward above the wrist and involve the forearm. 



Compound ganglion (tuberculous teno-synovitis) frequently affects the common 

 synovial sac of the flexor tendons and not infrequently that of the longus pollicis. 



