Bones of the Skull Flashcards
The upper portion of the skull. It divides into two regions: the braincase that houses and protects the brain, and the rostrum that includes the upper jaw and bones that surround the nasal passages.
Cranium
The lower jaw. It is composed of two bones - the left and right dentary.
Mandible
An immovable contact zone between two bones.
Suture
A projection or protuberance from a bone that serves as a point of attachment for muscles.
Process
A rounded protuberance of bone that serves as an articulation point with other bones.
Condyle
A canal that penetrates a bone and allows for passage of nerves and blood vessels.
Foramen
A pit or depression in a bone; the site of attachment for muscles or for articulation with another bone.
Fossa
The socket in the skull where the eyeball is situated.
Orbit
Paired bones located inside the nasal passages; looks spongy.
Turbinate
Paired bones anterior to the maxillae. Hold the incisors.
Premaxilla
Paired bones posterior to the premaxillae. Hold all upper teeth except for incisors.
Maxilla
Paired bones between the maxilla and frontals. Dorsal to the maxillae.
Nasal
Paired bones between the nasals and parietals. Help form the dorsal part of the braincase.
Frontal
Paired bones at the juncture of the maxillae, frontals, and jugals.
Lacrimal
Paired bones that form the anterior-most portions of the zygomatic arches. Between the maxillae and squamosals.
Jugal
Paired bones between the frontals and supraoccipital. Help form the roof of the braincase.
Parietal
Single bone between the parietals and supraoccipital. Not present in many mammals.
Interparietal
Paired bones that form the posterior most portions of the zygomatic arches and the lateral walls of the braincase. Between the jugals, parietals, and occipital bones.
Squamosal
Paired bones on the ventral surface of the cranium. Between the maxillae and the pterygoids. Form the “roof of the mouth.”
Palatine
Single bone that forms the floor and septum of the nasal cavity. Anterior to the prephenoid.
Vomer
Single, complex bone between the vomer and the basisphenoid. Parts of the bone help form the lateral walls of the braincase.
Presphenoid
Paired bones consisting of thin sheets that are situated on top of the presphenoid and alisphenoid bones.
Pterygoid
Paired bones to the sides of the prephenoid and basisphenoid. Parts of these bones help form the lateral braincase.
Alisphenoid
Single bone between the presphenoid and the basioccipital.
Basisphenoid
Single bone between the foramen magnum and the basisphenoid.
Basioccipital
Paired bones between the supraoccipital and the foramen magnum. The occipital condyles are always attached here. Help form the rear of the braincase.
Exoccipital
Single bone between the parietals and the exoccipitals. Helps form the rear braincase.
Supraoccipital
Paired bones that form the lower mandible. Hold all of the lower teeth.
Dentary
Space between the incisors and the molariform teeth. Only occurs in species that lack canines.
Diastema
Uppermost process on the dorsal projection of the dentary.
Coronoid process
Rounded process on the dentary that articulates with the glenoid fossa on the squamosal. Always between the coronoid process and the angle of the jaw.
Mandibular condyle (condyloid process)
Posterior most projection of the dentary. Always below the condyloid process.
Angle of the jaw
Depression in the squamosal bone where the dentary bone articulates.
Mandibular fossa (glenoid fossa)
Opening in the base of the braincase through which the spinal cord passes.
Foramen magnum
Downward pointing, spike-like projection of the exoccipital bone. Located directly behind the auditory bullae.
Paraoccipital process
Smooth raised surface on the exoccipital bone where the skull articulates with the first vertebrae
Occipital condyles
Bony capsule enclosing the middle ear.
Auditory bullae
Passage leading from external ear opening to the eardrum
External auditory meatus
A ridge on the dorsal surface of the skull that extends rearwards from the orbits the edge of the supraoccipital bone.
Sagittal crest
Ridge extending laterally across the skull along the juncture of the parietals and the supraoccipital.
Lambdoidal crest
An arch of bone formed by the jugal and squamosal that extends from the rostrum to the braincase. Forms the case of the orbit and protects the eye.
Zygomatic arch
A pit or open space located just anterior to the lacrimal. Characteristic of cervids.
Prelacrimal vacuity
Maxilla where the bone has numerous small openings or honeycombs.
Fenestrated maxilla
Hole in the roof of the mouth at the juncture of the premaxilla and maxilla.
Incisive foramen
An opening in the maxilla that leads into the orbit.
Infraorbital foramen
Projection from the frontal bone behind/above the orbit.
Postorbital process
