PHYSIOLOGY OF THE FOOT. 265 



Tlie sensitive lamin/c (see Plate X. Fig 4 . h). — In de- 

 scribing the hoof, I observed that its internal surface was 

 Hned with numerous horny lamellae. The subjects of our 

 present inquiry are, on the contrary, highly sensitive and 

 vascular. The whole circumference of the coffin bone is 

 covered with these sensitive leaves, each of which is received 

 between and firmly attached to two of the horny laminae of 

 the hoof (see Plate X. Fig 2 .h). It is, therefore, evident 

 that the surface of attachment between the hoof and the 

 internal parts must be in an extraordinary degree strong. 

 A partial observer of the foot of the horse would be led to 

 suppose that the sole endured the weight of the animal ; 

 which opinion would be erroneous ; on the contrary, we 

 find the sensitive sole can bear httle continued pressure, 

 though its elasticity and form enable it to bear a momentary 

 force. 



DESCRIPTION OF PLATE X. 



FOUR VIEWS EXEMPLIFYING THE VARIOUS STRUCTURES OF 



THE "Foot. 



Fig. 1 . The pastern and foot divided through the centre. — 

 a, The cannon bone ; h, the large pastern bone ; c, the small 

 pastern bone ; d, the pedal bone ; e, the navicular bone ; 

 /, the insertion of the extensor pedis tendon into the coro- 

 nary process of the pedal bone ; g, the insertion of the flexor 

 pedis perforans, passing under the navicular bone, to gain 

 insertion into the sole of the pedal bone ; h, the elastic frog ; 

 i, the horny frog ; j, the hoof; U, the coronet. 



Fig. 2. The hoof sawn offhelow the coronet. — a, The elastic 

 frog ; & 6, the posterior portion of the lateral cartilages ; c c, 

 the anterior portion of the lateral cartilages cut through ; d, 

 the flexor pedis perforans tendon, running under the navi- 

 cular bone, but above the elastic frog ; e, the navicular bone, 

 the anterior portion of which has been divided ; /, the supe- 

 rior surface of the pedal bone, showing the indentations for 

 the reception of the prominences at the inferior extremity of 

 the small pastern bone ; ^, in the separation of the hoof a 

 removal has taken place of the coronary process, which con- 

 sequently projects above the horny box in the living subject ; 

 h, the interweaving of the sensitive and of the horny or in- 



