3 66 



APPLIED ANATOMY. 



Suppuration in the Sheaths of the Tendons. If the sheath of the 

 tendons of the hand or fingers become infected, either by being penetrated by a 

 foreign body or by extension from the surrounding tissues, the pus travels along 

 the tendon as far as the sheath extends. 



The sheaths of the tendons vary in their extent. The flexor profundus and 

 sublimis tendons lie together in single sheaths, which commence at the base of the 

 distal phalanx. That of the thumb follows the long flexor tendon up the thumb, be- 

 neath the annular ligament, to 3 or 4 cm. (ij^ in.) above the wrist; that of the little 

 finger passes up to almost opposite the level of the web of the thumb and then 

 spreads over toward the radial side and envelops the remaining tendons of the other 

 three fingers, forming the great carpal bursa which extends up under the annular 

 ligament to 3 or 4 cm. above the wrist (Fig. 380). 



The sheaths of the remaining three fingers extend only to the heads of the met- 

 acarpal bones, about 2 cm. ( ^ in. ) above the webs of the fingers. This would leave 



Pointing above the anterior 

 annular ligament 



Pointing on each side of the 

 triangular portion of the 

 palmar fascia 



Pointing between the fibres 

 of the palmar fascia 



Pointing in the webs of the fingers 



FIG. 379. Cadaveric preparation with wax injected beneath the palmar fascia to illustrate where palmar abscesses 



tend to find an exit. 



a space of about 2 cm. ( ^ in. ) intervening between the proximal ending of the tendon 

 sheaths of the middle three fingers and the great carpal bursa. This is the usual 

 arrangement, but not infrequently the sheath for the little finger ends, as do the 

 other three, opposite the head of the metacarpal bone, or it may go up the entire 

 way to the wrist as a separate sheath, in which case the great carpal bursa envelops 

 only the tendons of the index, middle, and ring fingers. 



When suppuration occurs in the sheath of the thumb or little finger it is much 

 more serious than in the other three, because the pus tends to travel directly upward 

 and involve the palm, and go even above the wrist. When suppuration involves the 

 index, middle, or ring fingers it stops when it reaches the vicinity of the metacarpo- 

 phalangeal joints and involves the palm and carpal bursa only by breaking through 

 its own sheath and breaking into the carpal sheath. This it is not likely to do 

 unless the infection is virulent and the suppuration abundant. 



Suppuration Involving the Fingers. When suppuration occurs in the 

 middle or proximal phalanx the pus may occupy the tissue between the skin and 

 tendon, and not involve its sheath, hence is not liable to extend rapidly. When the 



