Bones and cavities of the facial cranium

TMJ

Anterior Skull

frontal bonefrontal bone

supraorbitsupraorbital al foramenforamenzygomatic bonezygomatic bone

maxillarmaxillary boney bone

alveolar fossaalveolar fossa

infraorbitainfraorbital foramenl foramen

glabella

mental foramenmental foramenmandiblemandible

mandibulmandibular ar symphysissymphysis

Anterior Skull

nasal nasal boneboneperpendicularperpendicular

plateplate

middle nasalmiddle nasalconchaconcha

vomer bonevomer bone

superior superior orbital fissureorbital fissureinferior nasalinferior nasal concha boneconcha bone

Paranasal Sinuses

frontal sinusfrontal sinus

ethmoid ethmoid sinussinusmaxilary sinusmaxilary sinus

sphenoid sinussphenoid sinus

Craniumfrontal bonefrontal bone

parietal boneparietal bone

occipital boneoccipital bone

lambdoidallambdoidal suturesuture

sagittal suturesagittal suture

coronal suturecoronal suture

Ventral Skullpalatine processpalatine process

palatine bonepalatine bone

vomer bonevomer bone

mastoid processmastoid process

styloid processstyloid process

external occipitalexternal occipitalprotuberanceprotuberance

sphenoid bonesphenoid bone

temporal temporal bonebone

occipital boneoccipital bone

Occipital bone

occipitaloccipitalcondylecondyle

jugularjugularforamenforamen

carotidcarotidcanalcanal

foramen magnumforamen magnum

Lateral Skull

lacrimallacrimalbonebone

temporaltemporalbonebone

squamosalsquamosalsuturesuture

mandibular mandibular condylecondyle

In mandibular In mandibular fossafossa

(TMJ joint)(TMJ joint)

external acousticexternal acousticmeatusmeatus

angleangle

coronoicoronoid d processprocess

zygomatic archzygomatic arch

mastoid processmastoid process

styloid processstyloid process

sphenoid sphenoid bonebone

bodybodyramusramusmandiblemandible

Lateral Skull

sutural sutural bonebone

crista gallicrista gallicribriborm platecribriborm plate

intenal intenal acoustic acoustic meatusmeatus

greater winggreater winglesser winglesser wing

optic canaloptic canalsella turcicasella turcica

jugular foramenjugular foramen

Internal Skull

Hyoid boneHyoid bone

temmporaltemmporalmandibularmandibular

jointjoint

external external acousticacousticmeatusmeatus

Hyoid +

________________________________________________SagittalSagittal

CoronalCoronal

LambdoidLambdoid

SquamousSquamous

Overview of Skull Geography

• Facial bones form the anterior aspect• The cranial bones enclose the brain

Vault• The cranial vault

or calvaria forms the superior, lateral, and posterior aspects of skull

• The cranial base forming the inferior aspect of skull

Cranial Base• Cranial base forms

the skull’s inferior aspect

• Three prominent ridges divide the base into fossae

• The brain rests on these cranial fossae completely enclosed by the cranial vault

• The brain occupies the cranial cavity

Cranium

• The 8 cranial bones include; 2 parietal, 2 temporal frontal, occipital, sphenoid, ethmoid

• Cranium is self- bracing allowing the bones to be thin, yet strong

Occipital bone• Forms most of the

posterior wall and base of skull

• Articulates with parietal & temporal

• Joins w/ sphenoid in the cranial floor

• Forms internal walls of posterior cranial fossa

Occipital bone - Int. landmarks

• Hypoglossal canal, Posterior cranial fossa

Temporal Bone• Forms the infero-

lateral aspects of the skull

• Parts of the cranial floor

• Divided into four regions; squamous tympanic, mastoid, and petrous-(int)

Temporal Bone• The internal

petrous region contributes to the cranial base

• The petrous region and the sphenoid bone form the middle cranial fossa

Temporal Bone - landmarks• Zygomatic

process– Meets the

zygomatic bone

– Forms the cheek

• Mandibular fossa– Receives

condyle of mandible

Temporal bones - landmarks• Stylomastoid

foramen– exit for facial

nerve

• Carotid canal– entrance for

the carotid artery which supplies blood to cerebral hemispheres

Sphenoid bone• Bone spanning the

width of middle cranial fossa

• Articulates as central wedge of all cranial bones

• Consists of central body and three processes; greater and lesser wings and pterygoid process (pos. view)

Sphenoid - landmarks

• Sella turcica (enclosure for pituitary gland)• Optic foramina (passage of optic nerves)• Superior orbital fissure (Nerves III, IV, V enter orbit)• Foramen rotundum & ovale (Cranial Nerve V to face) • Foramen spinosum (Middle meningeal artery)

Ethmoid bone• Forms most of the

area between the nasal cavity & orbits of eyes

• Lies between nasal bones & sphenoid

• Complex shape gives rise to nasal septum, sinuses and cribiform plate

Ethmoid bone - landmarks• Cribiform plates– Forms roof of nasal

cavity

• Olfactory formina– Olfactory nerves

enter brain

• Crista galli– Attachment of the

dura mater which secures brain in cavity

Facial bones• Consists of 14

bones w/ only mandible and vomer unpaired

• Others include maxillae, lacrimals, nasals, zygomatics, inferior nasal conchae, and palatines (not pictured)

Mandible• Forms the lower

jaw• Largest, strongest

bone of the face• It has a body and

two upwardly projecting sections called rami

• Houses lower dentition

Mandible - landmarks• Mandibular angle• Mandibular notch• Coronoid process• Mandibular

condyle• Alveolar margin• Mandible formina• Mental formina• Ramus of mandible

Maxillary bone• Forms upper jaw

and central portion of facial skeleton

• Fused medially• Articulates with

all facial bones except mandible

• Upper dentition• Forms 2/3 of

hard palate of the mouth

MaxillaryMaxillarybonebone

Zygomatic Zygomatic processprocess

Maxillary bones - landmarks• Alveolar margin– Upper dentition

• Frontal process– Forms lateral

aspects of nose

• Zygomatic process– Articulates with

zygomatic bone

• Maxillary sinuses – (Fig. 7.11)

Palatine bones• The horizontal

plates forms the posterior portion of hard palate

• Vertical plate forms part of the posterolateral wall of nasal cavity and a small portion of orbit

Palatine bones - landmarks• Horizontal plate– Posterior section

of hard palate

• Vertical plate– Part of the

posteriolateral walls of nasal cavity

• Orbital surface– Part of inferior

medial aspect of orbit

Vomer• Forms part of

the nasal septum

• Discussed with the nasal cavity

Vomer - landmarks• Plow shape– Divides nasal

septum into right and left parts

Inferior Nasal Conchae - Landmark

• The Inferior nasal conchae is just one of three in the nasal cavity

• Superior and middle concha are on the Ethmoid bone

The Orbits

Paranasal sinuses • Note positioning

around nasal cavity

Paranasal sinuses • Sphenoid sinus• Frontal sinus• Ethmoid sinus• Maxillary sinuses

Hyoid bone

• Body– Neck muscle

attachment

• Greater horn– Neck muscle

attachment

• Lesser horn

TMJ

TMJ Capsule

TMJ Capsule

TMJ Motions

TMJ Motions

The Skull: Fractures

• Egg Shell Fracture of the Parietal bones.

• Results from a fall or blunt force to the head

The Skull: Fractures

• Another example of an egg shell fracture.

Knife in Skull Above OrbitAP Projection