REGIONAL ANATOMY 33 
‘spreading over the insertion of the extensor pedis, the 
lower half of the external face of the lateral cartilages, 
the pulbs of the plantar cushion, the pyramidal body, the 
anterior portion of the plantar surface of the os pedis, and 
over the anterior face of the same bone. In turn, as the 
‘human foot with its sock is covered by the boot, this is 
encased by the hoof, the formation of which we shall study 
later. 
To expose the membrane for study the hoof must be 
removed. This may be done in two ways. By roasting in 
a fire, and afterwards dragging off the horny structures 
with a pair of pincers, a knife having first been passed 
round the superior edge of the horny box. Or by macera- 
tion in water for several days, when the hoof will become 
loosened by the process of decomposition, and may be 
easily removed by the hands. The latter method is less 
likely to injure the sensitive structures, and will expose 
them with a fresh appearance for observation. 
For purposes of description the keratogenous membrane 
is divided into threé regions: 
1. The Coronary Cushion. 
2. The Velvety Tissue. 
3. The Podophyllous Tissue, or the Sensitive Lamine. 
1. THe Coronary Cusuion.—In the foot stripped of the 
hoof the coronary cushion is seen as a rounded structure 
overhanging the sensitive lamine after the manner of a 
cornice. It extends from the inner to the outer bulbs of 
the plantar cushion, and is bounded above by the perioplic 
ring, and below by the lamine. 
When in situ it is accommodated by the Cutigeral Groove, 
a cavity produced by the bevelling out of the superior 
portion of the inner face of the wall of the hoof. Its 
superior surface is covered by numerous elongated papilla, 
set so closely as to give the appearance of the ‘pile’ of 
velvet. This is observed to the best advantage with the 
foot immersed in water. 
The Superior Border of the cushion is bounded by the 
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