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Periople Coronary
band

Coronary
corium

Stratum medium
of the hoof wall
Laminar corium

Interdigitation of
sensitive laminae
and insensitive
laminae

Stratum medium

Figure 8-7. Relationship between the corium of the coronary region (coronet) and the hoof wall. Insert,
the gross location of this section. Note the cross‐sectional appearance of the laminae. Source: Baxter,
2011. Reproduced with permission of John Wiley & Sons, Inc.

The periosteum on the convex surface laminae to the hoof wall rather than
of the distal phalanx blends with longitudi- directly to the sole of the foot.
nal leaves of corium called the laminar Inflammation of the laminae is lamini-
corium, which, because it is well inner- tis. Because the hoof is a relatively closed
vated, is often called the sensitive laminae space, such inflammation is extremely
of the hoof. The sensitive laminae inter- painful. Laminitis of sufficient severity can
digitate with epidermal laminae (Figs. 8‐7 result in detachment of insensitive from
and 8‐8), which, because they are not sensitive laminae so that the intimate asso-
innervated, are described as insensitive ciation between hoof wall and distal pha-
laminae. The large surface area afforded lanx is lost (Fig. 8‐9). In such a case, the
by thousands of interdigitating laminae distal phalanx may rotate downward, and
creates a strong connection between the the hoof wall grows abnormally, producing
distal phalanx and the hoof wall. Most of an irregular flared wall and up‐curled toe.
the weight of the horse is transferred by the This chronic condition is founder.