TABLE OF CONTENTS - National Zoo

Condyloid process - The projection on the upper rear portion of the mandible bearing
the mandibular condyle. The latter articulates with the upper jaw at the mandibular
fossa of the squamosal bone. The condyle varies substantially in shape because of
differing patterns of jaw movement involved with different dietary requirements. In
some carnivores (e.g., Mustelidae (black-footed ferrets)) the hinge formed at the
joint is firmly constructed and the lower jaw can be removed form the upper jaw only
with difficulty. This adaptation prevents disarticulation of the mandible as the
predator struggles with its prey. In herbivores the joint tends to be loose in order to
allow the flexibility of jaw motion necessary for grinding coarse vegetative matter.
Angular process - A process of variable size at the posteroventral edge of the lower
jaw. It is enormous in some herbivores, particularly rodents, providing a large
surface area for insertion of the masseter muscles. Marsupials and some rodents are
characterized by an angular process that is markedly inflected (bent inward), thus
providing a large area of insertion for the jaw muscles.
Masseteric fossa - The lateral depression of the lower jaw ventral to the coronoid
process into which much of the masseter muscle inserts.
Teeth
Incisors - These teeth are the anteriormost teeth in the jaws of most mammals. The
upper incisors reside wholly on the premaxillae. Incisors are ordinarily simple in
structure but are modified in many mammals for grooming, cropping, cutting, and
other functions.
Canines - There is one pair of these stabbing teeth on both the upper and lower
jaws. On the upper jaw each canine is located at the suture between the premaxilla
and maxilla. The tusks found in many mammals are usually modified canines. Some
mammals, particularly herbivores, lack canines and have a large gap, or diastema,
between the incisors and premolars. In others the canines are poorly developed and
peg-like.
Cheekteeth - An inclusive term for all the teeth occurring in the cheek region. They
include the premolars and molars of both jaws. The cheekteeth tend to be highcrowned
(hypsodont) in mammals with course diets, such as grazers, and lowcrowned
(brachydont) in mammals with soft diets, such as frugivores and omnivores.
Details on these teeth follow.
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