Agriculture Reference
In-Depth Information
Figure 6.19
Superfi cial structures of the head.
its function is to absorb shocks when the hoof touches on
uneven ground.
There are two groups of dermal structures correspond-
ing to the wall of the hoof and to the sole, and they are
collectively called “corium” (pl. coria). The corium does
not attach to the bones. It lies on a connective tissue pad
interposed between the dermis (the corium) and the bone
(the third phalanx). The structures corresponding to the
wall of the hoof are in a proximodistal order—the perioplic
corium, the coronary corium, and the laminar (lamellar)
corium—on both axial and abaxial aspects. The dermal
corium of the sole is called solear corium. With the excep-
tion of the lamellar corium, the other coria are provided
with papillae (Figure 6.20 e, f, g).
The hoof itself (sometimes referred to as the hoof
capsule) is a horny structure, consisting of the wall, the
sole, and the bulb of the hoof.
With the foot on the ground, the wall shows both axial
and abaxial aspects. The abaxial aspect can be arbitrarily
divided into three zones: the toe (in the dorsal position),
the quarter in the middle, and the heel (in the palmar/
plantar position). In the goat, the sole is reduced in size,
and it does not touch fl at ground while the goat is standing;
therefore, the weight of the body is bearing by the wall and
the bulb of the hoof. If the ground is not fl at upon contact
with the sole, the digital cushion absorbs part of
the shock. There is a narrow zone of periople (a thin and
shiny protective layer of transitional epidermis) outside,
and in a proximal position of the wall. Distal to the periople
is the hard wall of the hoof. Toward the palmar/plantar
aspect of the hoof, the periople covers the bulb of the hoof.
The sole is pointed dorsally and touches the irregular
bulb of the hoof palmarly/plantarly. There is a “white
zone” between the sole and the wall of the hoof. The bulb
of the hoof is an irregular horny structure that continues
with the bulb of the heel (Figure 6.20 a, b, c, d). The bulbar
horn (epidermal) covers and protects the bulbar corium
(dermal). In the goat, the bulbar horn is soft.
