Crainal Bones & Markings

Frontal Bone

forms the forehead, superior part of the orbit, and floor of the anterior cranial fossa

Supraorbital Notch

opening above each orbit allowing blood vessels and nerves to pass

Glabella

smooth area between the eyes

Zygomatic Process & arch

a bridgelike projection that articulates with the zygomatic bone to form the zygomatic arch

Mandibular fossa

located on the inferior surface of the zygomatic process; recieves the condylar process of the mandible to form the temporomandibular joint

Styloid process

needlelike projection that serves as an attachment point for ligaments and muscles of the neck. (This process is often missing from demonstration skulls because it has broken off).

Mastoid process

located posterior to the external acoustic meatus; serves as an attachment point for neck muscles

External occipital protuberance

midline prominence posterior to the foramen magnum

Occipital condyles

rounded projections lateral to the foramen magnum that articulate with the first cervical vertebra (atlas)

Greater wings

project laterally from the spheniod body, forming parts of the middle cranial fossa and the orbits

Lesser wings

form part od the floor of the anterior cranial fossa and part of the orbit

Pterygoid processes

project inferiorly from the greater wings; attachment site for chewing muscles (pterygoid muscles)

Sella turcica

"turkish saddle" located on the superior surface of the body; the seat of the saddle, called the hypophyseal fossa, holds the pituitary gland

Crista galli

"rooster's comb"; a superior projection that attaces the dura mater, helping to secure the brain within the skull

Cribiform plate

located lateral to the crista galli; form a portion of the roof of the nasal cavity and the floor of the anterior cranial fossa

Perpendicular plate

inferior projection that forms the superior portion of the nasal septum

Superior and middle conchae

extend medially from the lateral masses; act as turbinates to improve airflow through the nasal cavity

External acoutstic meatus

canal leading to the middle ear and eardrum

Jugular foramen

located where the petrous part of the temporal bone joins the occipital bone. Forms an opening which the internal jugular vein and cranial nerves IX, X, and XI pass

Carotid canal

opening through which the internal carotid artery passes into the cranial cavity

Hypoglossal canal

opening medial and superior to the occipital condyle through whoch cranial nerve XII (the hypoglossal nerve) passes

Foramen magnum

large opening in the base of the bone, which allows the spinal cord to join with the brain stem

Optic canals

openings in the base of the lesser wings; cranial nerve II (optic nerve) passes through to serve the eye

Foramen rotundum

openings located in the medial part of the greater wing; a branch of cranial nerve V (maxillary division) passes through

Foramen ovale

openings located posterolateral to the foramen rotundum; a branch of cranial nerve V (mandibular division) passes through

Foramen spinosum

openings located posterolateral to the foramen ovale; provides passageway for the middle meningeal artery

Foramen lacerum

almost completely closed by cartilage in the living person byt forms a jagged opening in dried skulls

Stylomastoid foramen

tiny opening between the mastiod and styloid processes through which cranial nerve VII leaves the cranium

Superior orbital fissure

slits in the oribits providing passage of cranial nerves that conrtrol eye movements (III, IV, VI and the opthalmic dividion of V)

Cribiform Foramina

tiny holes in the cribiform plates that allow for the passage of filaments of cranial nerve I (olefactory nerve)

Coronal suture

running in the frontal plane, where the parietal bones meet the frontal bone anteriorly

Sagittal suture

occurs where the left and right parietal bones meet superiorly in the midline of the cranium

Squamous sutures

occurs where a parietal bone and temporal bone meet on the lateral aspect of the skull

Lambdiud suture

occurs where the parietal bones meet the occipital bone posteriorly