Cranium

function of cranium

supports and protects the brain

Bones of the cranium (8)

frontal, parietal (2), occipital, temporal (2), sphenoid, ethmoid

squamous suture

Between parietal and temporal bones

lambdoid suture

between parietal bones and occipital bone

coronal suture

between frontal and parietal bones

sagittal suture

between the two parietal bones

fontal (anterior) fossa

primary frontal bone

middle ( temporal) fossa

primary body of sphenoid and temporal bones

posterior (Infratentorial) fossa

formed by occipital and temporal bones

parietal bone of skull

-paired

-forms the lateral part and roof of the cranium

vertex

superior point

found between parietal bones

frontal bone

Forms the forehead (vertical)

orbital plate

roof of each orbit, part of the frontal bone

Where are the frontal sinuses located?

located at anterior midline

What are the frontal sinuses?

Air-filled spaces within the frontal bone.

Where do the frontal sinuses drain?

middle meatus and nasal cavity

Supraorbital notch/foramen

passage for nerves and arteries

Ethmoid bone

-smallest cranial region

-cube shaped

Where is the Ethmoid bone Located

between the orbits

What do Ethmoidal sinuses contain?

3-18 air cells

cribiform plate

horizontal portion of ethmoid bone

What does the cribiform plate contain?

many formina for passage of OLFACTORY nerves

Where is the cribiform located?

on the floor of the anterior cranium

Crista galli

first vertical portion of Ethmoid bone

crista galli location

project superiorly from cribriform plate

attaches to falx cerebri

perpendicular plate

second vertical portion of the ethmoid

perpendicular plate location

-projects inferiorly from cribriform plate

-forms portion of bony nasal septum

labryinths

-The lateral portion of the ethmoid

- contain ethmoid air cells in ethmoid sinuses

superior and middle nasal conchae

thin sea shell-shaped bones located on the labyrinth portion of the ethmoid

superior and middle nasal conchae purpose

allow for humidification of air going into the lungs

sphenoid bone

ONLY bone to articulate with ALL cranial bones

What does the sphenoid bone form?

majority of the base of the skull/ middle fossa

Location of sphenoid bone

midline of cranium

Sella turcica

depression in the sphenoid bone where the pituitary gland is located

pituitary gland

master endocrine gland

What surrounds the sella turcica?

anterior and posterior clinoid processes

Where are the lesser wings of the sphenoid located?

lateral projections anterior and superior to sella turcica

What do the lesser wings of the sphenoid form?

posterior orbital wall

What do the lesser wings of the sphenoid contain

OPTIC CANAL

What passes through the optic canal found in the lesser wings portion of the sphenoid?

OPTIC NERVE and opthalamic

optic nerve

vision

Greater wings of the sphenoid

Are projections that project inferior and laterally•

Pterygoid processes

Serves as an attachment site for pterygoid muscles used in moving the lower jaw.

Pterygoid processes location

Extend downward from the sphenoid bone from the junction between the greater wings and the body

What is the sphenoid sinus?

An air-filled space located within the central portion of the sphenoid bone.

Where is the sphenoid sinus located in relation to other paranasal sinuses?

It is the most posterior of the paranasal sinuses.

located inferior to the sella turcica

Sphenoid foramina location

in sphenoid

What does the Sphenoid foramina transmit

nerves and vessels

The sphenoid foramina includes

lacerum

superior fissure (L. superior part of sphenoid)

rotundum: (L. middle portion of sphenoid)

spinosum(L. inferior portion of sphenoid)

ovale (R. inferior portion of sphenoid)

optic (R. superior portion of sphenoid)

Occipital bone

forms the inferioposterior portion of the cranium

4 parts of occipital bone

squamous, 2 occipital condyles, basilar portion

lateral occipital condyles of occipital bone

-2

-articulate with c1 of spine (atlas)

squamous part of occipital bone

The largest part of the occipital bone

includes external occipital protuberances (EOP)

clivus

- found in occipital bone

-Bony structure at the base of the skull.

-slopes down into foramen magnum

clivus purpose

provides a platform for brainstem

foramen magnum

inferior portion of the occipital bone

largest opening in skull

foramen magnum location

base of skull in occipital bone

Foramen magnum functioin

allows brainstem to continue as spinal cord

temporal bone

-forms the inferior lateral wall of the cranium and the most middle cranial floor

-paired

Four portions of the temporal bone

squamous, tympanic, mastoid, petrous

squamous portion of temporal bone

-largest

-contains zygomatic process

tympanic portion of temporal bone

-2

-form the majority of External Auditory Meatus (EAM)

What is the EAM and where is it located?

-ear canal

-located lateral side of the cranium

mastoid portion of temporal bone

-contains mastoid process (3)

- encloses mastoid air cells

petrous part of temporal bone

houses the middle and inner ear structures for hearing

densest

What does the petrous contain

the styloid process

structure of ear

outer ear, middle ear, inner ear

External Ear consists of

auricle and external acoustic meatus (EAM)

middle ear

air filled cavity in the temporal bone

middle ear consists of

Eustachian tube

tympanic membrane

ossicles bones

Eustachian tube

auditory tube

what does the eustachian tube connect the middle ear to?

nasopharynx

what role does the eustachian tube play

plays role in pressure equalization

Tympanic membrane

eardrum

Ossicles

malleus, incus, stapes

inner ear

fluid filled

What does the inner ear consist of

cochlea, vestibule, semicircular canals

vestibule and semicircular canals

controll balance and equilibrium

cochlea

responsible for hearing