Northern Prairie Wildlife Research Center
auditory (tympanic) bulla the inflated bony capsule that encases the middle and inner ear.
basal length of skull the distance from the anterior border of the foramen magnum to the anterior margin of the premaxilla.
basilar length of skull distance from posterior border of the tooth socket of the median incisor to mid-ventral border of foramen magnum.
basioccipital bone that forms the ventral margin of the foramen magnum.
basisphenoid the median ventral bone lying between the auditory bullae anterior to the basioccipital.
breadth of braincase greatest width of skull in region where the brain is housed.
canine the most anterior tooth in the maxilla, found just behind the incisors; often long, stout, and cone-shaped.
cheekteeth premolars and molars.
condylobasal length distance from anterior border of the tooth socket of the median incisor to plane of posterior border of occipital condyles.
coronoid process of lower jaw (mandible) a dorsally projecting process anterior to the condyle (process that fits into the glenoid fossa of the squamosal bone).
crown the portion of a tooth extending above the gumline.
cusp a point on the crown of a tooth.
dentine lake isolated area of dentine surrounded by enamel.
diastema a gap separating molariform teeth from anterior ones, usually incisors.
external auditory meatus bony canal leading into the auditory bulla.
foramen an opening, orifice, or perforation through bone.
foramen magnum the opening in the posterior of the skull through which the spinal cord passes.
frontal a paired dermal bone of the dorsal part of the skull, located between the nasal and parietal bones.
greatest length of skull greatest distance between most anterior point of skull (excluding teeth) to most posterior point of skull.
horn permanent structure projecting from the skull of certain mammals, consisting of a bony core covered by keratin sheaths (keratin sheaths are shed annually in pronghorn).
incisive foramina paired perforations through the anterior end of the hard palate at the point where the premaxilla and maxilla meet (also called palatine slit).
incisor the most anterior of the four basic kinds of teeth; rooted in the premaxilla.
infraorbital opening (canal) passage from the anterior face of the orbit to the side of the rostrum, passing through the base of the maxillary process.
interorbital breadth least measurement across skull between orbits.
interparietal an unpaired bone in the roof of the skull located between parietals and supraoccipital.
keratin a protein material of which the covering of horns is composed.
lacrimal a bone of the skull located in front of the orbit.
lacrimal fossa a depression in the lacrimal bone anterior to the orbit.
mastoid a process on the temporal bone posterior to the auditory meatus.
maxilla bone that forms part of the roof of the mouth in which the upper molars, premolars and canines are rooted (found posterior to premaxilla).
maxillary breadth the width of the skull across the maxilla.
maxillary tooth row line of teeth in the maxilla (canines to molars).
molar a cheektooth situated posterior to the premolars and having no deciduous precursors.
molariform all teeth posterior to the canines; includes premolars and molars.
nasal a paired dermal bone medial and posterior to the external nares.
occipital condyles two knobs on the occipital bone flanking the foramen magnum.
occlusal pertaining to the surface of contact between the upper and lower teeth.
orbit the bony socket in which the eye is located.
palate bony plate formed by the palatine bones and palatal branches of the maxilla and premaxilla; separates the nasal passages from the oral cavity.
parietal a paired dermal bone of the roof of the skull, located between the frontal and occipital bones.
postorbital process a projection of the frontal bone which marks the posterior margin of the orbit.
premaxilla bone in which upper incisors are rooted.
premolars teeth located anterior to the molars and posterior to the canines.
rostrum the facial region of the skull lying anterior to a plane drawn through the anterior margin of the orbits.
sagittal crest dorso-medial longitudinal ridges on the brain case.
tooth row line of teeth from the incisors through the molars.
unicuspid a tooth with a single cusp.
zygomatic arch the arch of bone that forms the lateral border of the orbit and temporal fossa.
zygomatic breadth the greatest width across the zygomata, measured at right angles to the long axis of the skull.
zygomatic plate the expanded and flattened lower maxillary process.