Page 391 - Anatomy and Physiology of Farm Animals, 8th Edition

376 / Anatomy and Physiology of Farm Animals

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Figure 20-5. The cheek teeth of the young horse are fully formed but largely contained within the
bones of the face and mandible. The teeth slowly erupt over the life of the horse as the crowns are worn
by chewing of coarse feedstuffs.

105 205
111 110 109 108 107 106 104 103 101 202 204 206 207 208 209 210 211
102 201 203

403 401 302
411 410 409 408 407 406 404 402 301 303 304 306 307 308 309 310 311
405 305
Figure 20-6. Adult equine teeth identified via the modified triadan system. Midline is at the center of
this diagram; imagine the animal facing you with both dental arcades straightened into the rows extend­
ing to the sides of this figure. Numbering starts in the animal’s upper right arcade closest to midline with
tooth 101 (the first incisor).

Deciduous and permanent dental for­ upper right (the right side of the maxil-
mulas for domestic farm animals are lary arcade) are numbered in the 100s;
shown in Tables 20‐1 and 20‐2. those in the upper left are 200s; those in
Veterinary medical professionals have the lower left are 300s; and those in the
adopted a system of dental numbering lower right are 400s. The second and
called the modified triadan system, third numbers represent the number of
adapted from human dentistry. In it, the tooth as counted from rostral midline
each tooth has a unique, three‐digit and progressing caudad. Once mastered,
identifier. Imagine the mouth viewed the triadan system allows for the suc-
from the front and divided into four cinct and unambiguous identification of
quadrants (Fig. 20‐6). The teeth in the individual teeth in medical records.