DISEASES OF THE CLAWS AND FOOT PADS. 



The claws, the third phalanx, of the toe (the bone of the claw) 

 articulates with the second phalanx; near the articulatory surface is an 

 annular fold (claw fold) which receives the free border of the claw. 

 The phalanx tertia is covered by the cutis vera. This develops and 

 grows from the matrix of the claw plate (coronet), the claw bed, and the 

 muscular sole which is an extension of the corium which extends over 

 the third phalanx after dipping into the circular furrow at the base of 

 the bone (Fig. 1 22) . In order to protect the ends of the claws when not 



Fig. 122. — Nail. Longitudinal section of 

 nail. «, Matrix of nail horn; a', papillary 

 zone of nail horn: b, bed of na^l; c, mnt'ix 

 of cushion; d, cushion; e, nail. (.Siedain- 

 grotzlcy.) 



Fig. 123. — Diagram of the first and 

 second phalanx. a, Tubercle of pad; 

 b, horn groove; c, groove of sole; d, 

 third phalanx; e, dorsal ligament. 

 (Siedamgrotzky.) 



in use there is an elastic tendinous band which draws back the nail and 

 when the foot is on the ground the nail is retracted (Fig. 123) and the 

 v/eight of the body carried on the pads, those pillow-like elastic bodies, a 

 large one in the centre and four radiating in front of it, corresponding to 

 each toe, the thumb toe being too high up, does not get pressure (Fig. 124). 



Ingrowing Claws. Incarnatio Unguis. — Animals that are house pets 

 and have little or no exercise do not wear the nails properly and they 

 become long and are apt to strike the ground when walking. Occasion- 

 ally these nails l)ecome so long as to turn under and the weight of the 

 animal presses the claw into the pad and the claw is gradually buried in 

 the flesh. The dew or spur claws on the posterior extremities frequently 

 grow entirely round and grow into the pad, causing great irritation, 

 swelling and suppuration. It is extremely painful, the animal constantly 

 licking the affected pai't. It can be cut through by a pair of jeweler's 

 wire clippers, care being taken not to cut it too close and involve the 

 matrix. 



Splintei'ing, cracking and breaking of the claws are generally due to 

 some traumatism, although occasionally the claw falls off from purulent 



378 



