THE INTERNAL FOOT. 425 



rery rough. The upper border is marked by a deep groove 

 running back to the heel. From each of these grooves arises a 

 broad phitc of cartikge, called the lateral (side) cartilages. 

 These are rounded on their outside, but irregularly hollowed, 

 or concave, on their inside. They fill up the back corners of 

 the heel of the inside of the foot. Their upper part may be 

 felt under the 'skin of the heel, and their outline is even per- 

 ceptible to the eye. Their lower half is covered with the la- 

 mella?, the same as the coffin-bone, and, of course, by the wall 

 of the hoof. The superior (upper) portion of the coffin-bone is 

 occupied with the articulatory surface which inclines backward. 

 It presents a broad, more than half-moon, smooth face, hol- 

 lowed out, or concave, from before backward, the middle being 

 raised into a ridge, and the outer boundaries also being raised 

 slightly at each side, but very prominently above, wdiere it is 

 bounded by the coronary process. This face forms about three- 

 fourths of the lower articulating surface of the coffin-joint. At 

 the back of the bone, looking almost straight back, and extend- 

 ing from the inside of one wing to the other, and very nar- 

 row, is another smooth articulating surface, which articulates 

 with the upper half of the front border of the shuttle-bone. 



TJie navicular^ or shuttle-hone, bears some resemblance to a 

 weaver's shuttle. It is more rounded on its forward border 

 than on the hinder one. By its forward border, the upper 

 half of it, as we have just above stated, articulates with the 

 coffin-bone.- Its upper surface forms the posterior (hinder) 

 third of the lower articulating surface of the coffin-joint, 

 being similarly raised in the middle, and depressed toward 

 the ends of this bone, which terminates within the Avings of 

 the coffin-bone. The posterior border is slightly beveled, 

 and rough, for the attachment of an important broad tendon, 

 which, a little above, unites with the great flexor tendon. 

 Its under surface is smooth and*rounded, and marked by a 

 ridge running across it. It rests on the flexor tendon, which 

 passes under it to be attached to the coffin-bone. ' There is a 



