Figs. 98 loi. Palm of Hand (Left); Tendon-sheaths. 



After JoESSKi. and von Rustih )|<x. 

 (Cf. Fig. 97.) 



The tendon-sheaths of the P'lexor Muscles (Flexor Sublimis Digitorum and 

 Flexor Profundus Digitorum; Flexor Longus Pollicis) extend from a distance of 

 a little less than an inch above the Annular ligament far into the palm of the hand. 



There are generally two tendon-sheaths — one for the Flexor Sublimis 

 and Flexor Profundus Digitorum Muscles, another for the Flexor Longus Pollicis 

 Muscle — which are frequently in communication. 



The sheath of the Flexor Carpi Radialis Muscle extending from the 

 trapezium to the 2nd Metacarpal bone is of but little practical importance. The 

 large flexor tendon-sheath shews after inflation a bulging above the constriction 

 caused b)^ the annular ligament. On the inner side of the hand the sheath extends 

 lower down, and invariably communicates with the sheath for the tendons of the 

 little finger. 



In a similar manner the Sheath of the Flexor Longus Pollicis extends as 

 far as the Distal phalanx. 



This is a ver\' important point of practical application because suppuration 

 of the sheath of the thumb or of the little finger always extends into the main 

 sheaths; this does not occur in the case of the 2nd, 3rd or 4th digits. 



Moreover, we have herein an explanation of the extension of Suppuration 

 from the thumb to the little finger and vice versa — the inflammatory process 

 passing from the thumb to the main flexor sheath and into the sheath of the 

 Uttle finger owing to the free communication. 



The Median Nerve is situated between the main Sheaths and the Annular 

 Ligament whereas the Ulnar Nerve lies superficial to the ligament so that it only 

 comes in close relation with the main sheaths above and below this structure. 



The Ulnar Artery, not shewn in the figure, lies nearer the Sheaths than 

 the Ulnar Nerve. 



The Tendons of the Flexor Sublimis and Flexor Profundus muscles lie 

 in common sheaths as they extend down upon the fingers from tlie metacarpo- 

 phalangeal joints as far as the bases of the terminal phalanges, i. e. the insertion 

 of the Profundus tendons. 



Injury, therefore, to the terminal phalanges distal to these points would 

 not involve the sheaths. 



Figs. 99 and 100 depict .variations which are described by some authors 

 as normal — a third sheath being inserted as a wedge, between the two main 

 sheaths at their proximal end — . When this third sheath becomes markedl}'^ 

 developed (Fig. 100) tlie tendon of the Flexor Profundus passing to the Index 

 finger is transmitted through it. 



The somewhat complicated arrangement of the tendons of the long flexor 

 muscles is schematically represented in Fig. 101. 



The "Mesotendina" analogous to the Mesenteric folds, are shewn in the 

 cross-section. 



