Skull anatomy

Mandible

body: forms the chin ramus: vertical extension of the body mandibular condyle: articulation point with the mandibular fossa coronoid process: projection anterior to the mandibular condyle mandibular angle: where the body and ramus meet mental foramen: prominent opening on the body alveoli/alveolar process: sockets for lower teeth mandibular symphysis: anterior depression of the chin

Temporal bones

styloid process: needle-like projection zygomatic process: bridge-like structure joining temporal & zygomatic (cheek) bones mastoid process: rounded projection posterior to the ear mandibular fossa: rounded projection forming a socket for the jaw bone (mandible) external auditory meatus: "ear" canal

Floating Ribs

# 11 and 12 are free floating, DO NOT attach to Sternum

What is a Process?

A site for muscle attachment:

Lacrimal Fossa

Anterior and lateral depression of roof of orbit which accommodates the lacrimal gland

Sphenoid

Base and sides of skull; part of the eye orbits.

Occipital Bone Landmarks and Openings

Basilar portion of occipital External occipital crest External occipital protuberance (inion) Internal occipital protuberance Occipital condyles Jugular foramen (between occipital and petrous part of temporal) Foramen magnum Hypoglossal canal Clivus (finger slot above foramen magnum) Groove for sinuses Cerebellar fossa (smooth spaces for cerebellar hemispheres to sit) Superior nuchal line Inferior nuchal line

Mandible Bone Landmarks and Openings

Body (horizontal portion) Ramus (vertical portion) Angle of mandible Coronoid process (anterior process) Mental tubercle/protuberance Mental foramen

Jugular Foramen

CN IX, X, XI, superior bulb of internal jugular, inferior petrosal and sigmoid sunuses, meningeal branches of ascending pharyngeal and occipital arteries pass through

Occipital bones

Cranial foramen magnum: large opening at the base of the skull where the spinal cord joins the brain occipital condyles: rounded projections which articulate the atlas external occipital protuberance: large "bump" on the posterior surface (bump at the back of the head)

Sphenoid Bone

Cranial greater wings: form parts of the middle cranial fossa and external wall of the skull lesser wings: form part of the floor of the middle cranial fossa sella turcica: houses and protects the pituitary gland

Ethmoid

Cranial Next to nose crista galli: thin projection that anchors the dura mater to the skull cribriform plates: flat plates on either side of the crista galli

Glabella

Cranial ***

Cranial Fossae

Cranial fossae are shallow depression in the cranial floor where the brain rests.

Sutures

Cranial sutures are interlocking joints where the cranial bones meet. The suture lines have a serrated (saw-toothed) appearance that can easily be viewed on the external surface of the skull.

Palatine

Either of two irregularly shaped bones that form the back of the hard palate and helps to form the nasal cavity and the floor of the orbits

Maxillae

Facial bone alveoli/alveolar process: sockets for upper teeth infraorbital foramen: small opening under the orbit

What are the foramens found in the sphenoid bone?

Foramen rotundem Foramen ovale, Foramen lacerum Foramen spinosum

Maxilla

Forms most of the upper jaw, and part of the hard palate, contains upper molars, premolars, and canines

Frontal Bone Landmarks and Openings

Glabella (forehead between eyes) Nasion (between nasal and frontal bones) Supraorbital margin Frontal crest Supraorbital foramen (notch) Orbit roof (internal view)

Sphenoid Bone Landmarks and Openings

Greater wing Superior orbital fissure Lesser wing Inferior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Optic canal Pterygoid fossa—smooth spot between lateral/medial plates Sella turcica Anterior clinoid process Posterior clinoid process (horns)

Ethmoid

Internal base of skull; structures in nasal cavity.

Hyoid Bone

Is a bone in the body that does not articulate with any other bone. Its various landmarks (body and cornus (horns)) serve as attachment points for various muscles of the neck.

Sagital Suture

Located on the midline of the skull lies between both parietal bones (immovable joint)

Significance of a Foramen?

Location where Blood vessels and nerves have a passageway through bone

Cribiform plate

Location: • Ethmoid bone Description: • Bony plate with foramina (holes) that transmit olfactory nerves (CN I) Comment: • Contributes to anterior midline portion of anterior cranial fossa

Seperate Bone Landmarks and Openings

Nasal Bone (and septum) Vomer Bone Lacrimal Bone Inferior Nasal Concha Palatine Bone (posterior 1/3 of roof of mouth)

Optic Foramen

On either side ochiasmatic groove -transmits optic nerve (CN II) along with its meningeal coverings, and the ophthalmic artery

Frontal

Part of the cranial bones supraorbital foramen: small opening above each orbit supraorbital margin: superior ridge of each orbit (eyebrow) glabella: smooth surface between the orbits (between eyebrows)

Temporal Bone Landmarks and Openings

Squamous portion Petrous portion Internal auditory meatus External auditory meatus Carotid canal (inferior view) Stylomastoid foramen (inferior view) Styloid process Mastoid process Digastric notch (posterior to mastoid process) Zygomatic process of temporal bone Groove for middle meningeal artery ("Y" shaped)

Ethmoid Bone Landmarks and Openings

Superior nasal concha Crista galli Middle nasal concha Cribriform plate Perpendicular plate Paranasal sinus

Parietal Bone Landmarks and Openings

Superior temporal line Inferior temporal line

Alveolar Process

a ridge that forms the borders of the upper and lower jaws and contains the sockets of the teeth

Occipital Bone

a saucer-shaped membrane bone that forms the back of the skull

Openings in the Skull

allow nerves and blood vessels to pass through the skull.

Nasal Bone

an elongated rectangular bone that forms the bridge of the nose

Squamosal Suture

between parietal bone and temporal bone on side of the skull, bordered in back by occipital bone

Aveolar Process

bone surronding the teeth

Temporal Bone

bone that forms parts of the side of the skull and floor of the cranial activity. There is a right and left temporal bone.

Hyoid Bone

bone that is suspended in the mid neck region and provides a moveable base for the tongue

Sella turcica

depression in the sphenoid bone where the pituitary gland is located

Madibular fossa

depressions where manidble and cranium meet and join

Coronal

divides parietal and frontal bones

Lamboid

divides parietal and occipital bones

Squamosal

divides parietal and temporal bones

Sagittal

divides parietal bones

Palatine Bone

either of two irregularly shaped bones that form the back of the hard palate and helps to form the nasal cavity and the floor of the orbits

Parietal Bone

either of two skull bones between the frontal and occipital bones and forming the top and sides of the cranium

Palatine Process

forms the anterior portion of the hard palate (roof) of the mouth also forms parts of the nasal cavity and eye orbits

Anterior cranial fossa

holds the frontal lobes of the brain

External Auditory Meatus

hole in the temporal bone extending medially to the inner ear

Palatine

lie underneath the maxillae and form the floor of the nasal cavity

Inferior nasal Concha

located on each side of the nasal septum, attached to the lateral wall of the nasal cavity; increase epithelial surface area and create turbulence in the inspired air

Downward Facing Openings

o Foramen ovale—CN V3 (sphenoid) o Foramen spinosum—middle meningeal artery (sphenoid) o Olfactory foramen—Olfactory nerve (CN I) (ethmoid, Cribiform plate) o Foramen lacerum—Internal carotid artery (sphenoid) o Jugular foramen—CN IX, X, and XI (temporal) Internal jugular vein o Carotid canal (temporal) internal carotid artery

Lateral Facing Openings

o Internal auditory meatus— CN VII and VIII (temporal) o Hypoglossal canal—CN XII (occipital)

Forward Facing Openings

o Optic canal—optic nerve (CN II) (sphenoid) o Superior orbital fissure—(CNIII, IV, V1, and VI) (sphenoid) o Foramen rotundum—CN V2 (sphenoid)

Maxillary Bone Landmarks and Openings

o Palatine process of maxilla bone (anterior 2/3 of roof of mouth) o Incisive foramen (hole on roof of mouth behind front teeth) o Intermaxillary suture o Infraorbital foramen o Alveolar process (tooth bumps)

Zygomatic Bone Landmarks and Openings

o Zygomatic arch

Carotid Foramen

opening for carotid artery

Mastoid Process

projection of the temporal bone located behind the ear

Occipital Condyle

ridges on left and right of foramen magnum

Lacrimal Bone

small fragile bone making up part of the front inner walls of each eye socket and providing room for the passage of the lacrimal ducts

Styloid Process

spike-like process extending downward from the temporal bone on each side of the skull

Cribiform plate

superior surface of the ethmoid; perforated by a foramina which allows passage of the olfactory nerves, which provide sense of smell

Posterior cranial fossa

supports the cerebellum

Middle cranial fossa

supports the temporal lobes of the brain

Lambdoidal Suture

suture that separates parietal bones from occipital bone

Zygomatic Bone

the arch of bone beneath the eye that forms the prominence of the cheek

Condylar Process

the condyle of the ramus of the mandible that articulates with the skull

Temporomandibular joint (TMJ)

the joint between the head of the lower jawbone and the temporal bone

Frontal Bone

the large cranial bone forming the front part of the cranium: the forehead and the upper part of the orbits

Foramen Magnum

the large opening at the base of the cranium through which the spinal cord passes

Mandible

the lower jawbone in vertebrates

Middle nasal Concha

the middle thin, spongy, bony plate with curved margins, part of the ethmoidal labyrinth, projecting from the lateral wall of the nasal cavity and separating the superior meatus from the middle meatus;

Coronal Suture

the suture between the parietal and frontal bones of the skull

Vomer

thin trapezoidal bone of the skull forming the posterior and inferior parts of the nasal septum (the lower portion of the nasal septum)

Crista Galli

vertical projection providing a point of attachment for the dura mater, helping to secure the brain within the skull

Inferior Nasal Conchae

very thin, curved bones within the nasal cavity

Junctions

• Bregma • Lambda