74 



DISSECTION OF THE HAND. 



Dissection 

 of the flexor 

 tendons. 



Divide 



annular 



ligament 



and open 

 sheaths. 



Superficial 



flexor 



tendons 



in the hand 

 insertion ; 



slit for the 

 deep flexor. 



Dissection. 



Tendons of 

 deep flexor 



the first phalanx, and, after uniting with the digital nerve on 

 the back of the finger, is continued to the dorsum of the last 

 phalanx. 



Dissection. The tendons of the flexor muscles may next be 

 followed to their termination. To expose them, the ulnar artery 

 should be cut through below the origin of the deep branch ; and the 

 superficial volar branch of the radial having been divided, the 

 palmar arch is to be thrown towards the fingers. The ulnar and 

 median nerves are also to be cut below the annular ligament, and 

 turned downwards. 



A longitudinal incision is to be made through the centre of the 

 annular ligament without injuring the muscles that arise from it, 



and the pieces of the ligament 

 are to be thrown to the sides. 



Finally, the sheaths of the 

 fingers may be opened in order 

 to show 'the insertion of the 

 tendons. 



FLEXOR TENDONS. Beneath 

 the annular ligament the ten- 

 dons of the deep and superficial 

 flexors are surrounded by a large 

 and loose sy no vial membrane, 

 which projects upwards into the 

 forearm and downwards into the 

 hand, and sends an offset into 

 the digital sheath of the thumb, 

 and usually one into that of the 

 little finger (fig. 28). The syno- 

 vial sheath belonging to the ten- 

 don of the flexor longus pollicis 

 is often separate from the rest. 



FLEXOR SUBLIMIS. The ten- 

 dons of the flexor sublimis are 

 superficial to those of the deep 

 flexor beneath the ligament ; and 

 all four are nearly on the same level, instead of being arranged in 

 pairs as in the forearm. After crossing the palm of the hand they 

 enter the digital sheaths (figs. 29 and 30) ; and each is inserted by two 

 processes into the margins of the middle phalanx, about the centre. 

 As it enters the sheath, the tendon of the flexor sublimis conceals 

 that of the flexor profunclus ; but opposite the lower half of the 

 first phalanx it is split for the passage of the latter tendon. 



Dissection. To see the tendons of the deep flexor and the lum- 

 brical muscles, the flexor sublimis must be cut through above the 

 wrist, and thrown towards the fingers. Afterwards the synovial 

 membrane and areolar tissue should be taken away. 



FLEXOR PROFUNDUS. At the lower border of the annular liga- 

 ment the tendinous mass of the flexor prof undus is divided into four 

 pieces, though in the forearm only the tendon of the index finger is 



FIG. 28. SYNOVIAL SHEATHS OP 

 THE FLEXOR TENDONS. 



