180 ANATOMY AND PHYSIOLOGY OF THE HORSE’S FOOT. 
to the hoof in many cases is sufficient to hasten the develop- 
ment of this seeming defect, or even to produce it. At the 
Fig. 5. 
r 
c 
Lower or Plantar Surface of the Pedal Bone. a. Retrossal process, or heel. 
b. Plantar fissure, c. Plantar foramen, d. Imprint for the insertion 
of the deep flexor tendon, e. Toe of the bone. f. Space between 
the wings of the pedal bone for the lodgment of the navicular bone 
and the soft structures at the posterior part of the foot. g. Plantar 
fissure with blood-vessel entering the foramen, h. The sole of the bone 
removed to show the semilunar sinus, and converging and diverging 
canals through which arteries pass to form the circumflex artery 
around the lower margin of the foot. 
same time, I am quite ready to admit that it sometimes 
appears as a natural feature in the pedal bone of a foot that 
had never been submitted to the farrier’s treatment ; quite 
recently I have examined these bones in a colt, and they were 
deeply indented at the toe. 
Nearly the whole anterior and a portion of the lateral 
surface of the bone is pierced at various intervals by openings 
of different sizes for the passage of blood-vessels varying in 
calibre, from the most delicate hair-like tube to the vein 
nearly as thick as a goose quill ; and on the lateral surface, 
towards the wings, grooves, channels, and recesses, will be 
observed excavated out of the hard bone, like some of those 
fantastic caves and passages which the waves of the sea have 
been forming during long ages in rocks exposed to their 
ceaseless power. It is worthy of remark that the anterior 
surface of the bone is most extensively pierced by those canals 
