142 CLINICAL APPLIED ANATOMY. 



TenosynoYitis. Inflammation of the tendon sheaths of an acute 

 character occurs either from simple over-exertion, as in the flexor 

 sheaths of the wrist from rowing, or from infection by a punctured 

 wound, as in many cases of whitlow. 



Tendon Sheaths of Wrist and Hand. The flexor tendons as 

 they pass deep to the anterior annular ligament of the wrist are 

 covered with a synovial sheath of a large size which is common 

 to all except the flexor longus pollicis. This sheath extends 

 upwards for two fingers' breadth above the upper border of the 

 annular ligament. Downwards it tends to spread out upon the 

 tendons, terminating in three diverticula about the middle of the 

 metacarpal bones of the index, middle and ring fingers, but in 

 the case of the little finger, it is prolonged downwards as far as 

 the base of the terminal phalanx. In addition, the tendons 

 belonging to the three outer fingers have additional and separate 

 synovial linings to their sheaths, starting opposite the heads of 

 the several metacarpal bones, and ending at the bases of the last 

 phalanges. It will thus be seen that there is an interval between 

 the large common synovial sheath in the palm and the special 

 sheaths in these digits. 



The flexor longus pollicis tendon has its own sheath lined by 

 synovial membrane, which extends from about one-and-a-half 

 finger's breadth above the annular ligament continuously to the 

 base of the second or terminal phalanx of the thumb. Sometimes 

 this special synovial sheath communicates with the larger common 

 sheath near the annular ligament. 



Pricks of the pulp of the digits, as with a needle or pin, are 

 very apt to be followed by septic inflammation, leading to the 

 varieties of whitlow. It is easy to see how a synovial sheath may 

 become secondarily infected from this adjacent inflammation. 

 It is possible that at certain spots, particularly opposite the 

 interphalangeal joints where the fibrous sheaths are thin or 

 even fenestrated, the synovial membrane may bulge and become 

 primarily inoculated with bacteria. 



If the theca of the flexor tendons of the little finger is involved, 

 the inflammation may spread directly into the common synovial 



