THE HAND. 



367 



end phalanx is affected the affection is known as panaris, whitlow, felon, etc. The 

 pulp of the finger resembles that of the heel, the scalp, the palm of the hand, etc., 

 in the fact that the under surface of the skin sends off firm fibrous bands or fibrils 

 which are attached to the parts beneath. The spaces between these fibrils are filled 



Sheath of flexor 

 longus pollicis 



Palmar bursa 



Sheaths of flexor 

 tendons of the index, 

 middle and ring finger 



^ Sheath of flexor 

 tendons of little finger 



FIG. 380. Palmar bursa and sheaths of the flexor tendons distended with wax. 



in with fatty tissue and vessels, nerves and lymphatics (Fig. 381). Infection begins 

 in the skin through some small wound, as the tearing of the nail, pin-punctures, etc. , 

 and involves the fatty tissue beneath. If exit is not given to the pus it is often unable 



Extensor communis digitorurr . 



Flexor profundus digitorum . 

 Flexor sublimis digitorum 



FIG. 381. Longitudinal section of the end of a finger, showing the pulp and mode of termination of the tendons in 



the distal phalanx. 



to break through the hard skin on the surface. Since the fibrous bands prevent 

 swelling to any extent, it burrows deeper and involves the periosteum along which 

 it proceeds to the region of the joint, here it may enter the sheath of the tendon 

 when it rapidly proceeds upward as far as the sheath extends. 



