Cranium

neurocranium and viscerocranium

the cranium consists of 2 parts called what

neurocranium

also referred to as the cranial vault as it houses the brain, its meninges, supporting vasculature, and cranial nerve nuclei and associated fibers until they exit

calvaria

what is the roof of the neurocranium

cranial base

what is the floor of the neurocranium

8 bones

the neurocranium is formed by how many bones

frontal, ethmoid, sphenoid, occipital

what are the 4 singular bones that make up the neurocranium

temporal bone, parietal bone

what are the 2 sets of bones that have bilateral pairs in the neurocranium

fibrous interlocking sutures

in adults calvarial bones are united by what

facial skeleton

forms the anterior part of the cranium and consists of bones surrounding the mouth, nose, and most of the orbits

15 irregular bones

how many bones are there in the viscerocranium

mandible, ethmoid, vomer

what are the 3 singular bones in the viscerocranium

maxilla, inferior nasal conchae, zygomatic, palatine, nasal, lacrimal bones

what are the 6 paired bones of the viscerocranium

frontal bone

formed the forehead

- anteriorly articulates with nasal, maxilla, zygomatic, lacrimal, ethmoid, and sphenoid bones

nasion

intersection of the frontal and nasal bones

superciliary arch

ridge superior to the supraorbital margin

glabella

smooth are between the superciliary arches

zygomatic bones

forms the prominences of the cheeks, articulates with frontal, maxilla, sphenoid, and temporal bones

- forms the lateral part of the inferior wall of the orbits

trigeminal nerve maxillary division

small zygomaticofacial foramen found on the anterolateral aspect

- a sensory branch of _________ ________ ________ ________

orbits

formed by 7 bones

- roof, lateral wall, floor (inferior wall), medial wall

roof of orbit

frontal bone

- sphenoid bone

lateral wall of orbits

zygomatic bone

- sphenoid bone

floor of orbit

maxilla

- zygomatic bone

- palatine bone

medial wall

maxilla

- lacrimal bone

-ethmoid bone

- sphenoid bone

orbital fissures; optic canals

openings within the orbits include superior and inferior _______ ________ and _______ ________

maxilla bones

form the upper jaw

- paired bones united at the intermaxilary suture in the median plane

- alevolar processes include the tooth sockets

- surround most of the piriformis aperture

frontal, ethmoid, nasal, lacrimal, inferior nasal conchae, palatine, vomer, and zygomatic bones

the maxilla bone articulates with what other bones

infraorbital nerve

sensory branch of the maxillary nerve

palatine process

plates from both maxilla for the anterior portion of teh hard palate

nasal region

what region has a paired nasal bones articulate with the frontal and maxilla bones

paired inferior nasal conchae

a curled, scroll-like bony plate along the inferior part of the lateral nasal wall

nasal septum

formed by the perpendicular plate of ethmoid bone, vomer bone, and septal cartilage

parietal bone

paired bones participating in forming the roof

- articulates with frontal, occipital, temporal, sphenoid, and opposite parietal bones

superior and inferior temporal line

attachments site for temporalis muscle

part of the pterion region

location where parietal, frontal, temporal, and sphenoid articulate

temporal bone

paired bones participating in the formation of the temporal fossa

- articulates with the parietal, occipital, sphenoid, zygomatic, and mandible

temporal fossa

contains structures essential to hearing, balance, mastication

superior bone of the temporomandibular joint (TMJ)

mandibular fossa of the temporal bone articulates with the condyle of the mandible

squamous part of temporal bone

forms the lateral cranial wall above the ear

- contributes to the zygomatic arch

zygomatic arch

temporal process of the zygomatic bone and the zygomatic process of the temporal bone

tympanic part of temporal bone

helps form the inferior part of the external acoustic meatus

mastoid process of temporal bone

location of the mastoid process which is the site for SCM

petrous part of temporal bone

houses the middle and inner ear

styloid process

slender, pointed projection

- attachment site for styloglossus, stylohyoid, and stylohyoid ligament

external acoustic meatus

entrance to ear canal

internal acoustic meatus

transmits CN VII (facial) and VIII (vestibulocochlear)

stlyomastoid foramen

exit of facial nerve (CN VII)

carotid canal

passage of the internal carotid artery

jugular foramen

passage for glosopharyngeal (CN IX), vagus (CN X), spinal accessory (CN XI) nerves and internal jugular vein

sphenoid bone

single, unpaired, butterfly-shaped bone located in the central skull base

- articulates with nearly every other cranial bone

- contributes to the cranial floor, orbit, nasal cavity, and multiple major foramina

body of sphenoid

central portion

- sella turcica

--> tuberculum sellae

--> hypophyseal fossa (holds pituitary gland)

--> dorsum sellae

greater wings of sphenoid bone

forms part of:

- middle cranial fossa

- lateral wall of the orbit

foramen rotundum, foramen ovale, foramen spinosum

what are the key foramina of the sphenoid bone

lesser wings of sphenoid bone

forms part of the roof of the orbit

- has key openings in the optic canal

optic nerve (CN II), ophthalmic artery, superior orbital fissure lies between the lesser and greater wings

what things come out of the optic canal in the lesser wings of the sphenoid bone

pterygoid process

extends inferiorly from the junction of the body and greater wings

- medial pterygoid plate

- lateral pterygoid plate

- ptyergoid fossa lies between the 2 plates

oculomotor (CN III), trochlear (CN IV), abducent (CN VI), trigeminal (ophthalmic V1)

what travels through the superior orbital fissure

trigeminal maxillary V2

what travels through the foramen rotundum

trigeminal mandibular V3

what travels through the foramen ovale

middle meningeal artery

what travels through the foramen spinosum

lacrimal part of sphenoid bone

paired bones forming the anteromedial orbital wall

- smallest and most fragile bone in the face

- articulates with frontal, ethmoid, maxilla, and inferior nasal conchae

external acoustic opening

is the entrance of the external acoustic meatus (ear canal)

occipital bone

external occipital protuberance

- superior nuchal line, marking the superior limit of the neck, extends laterally from each side of this protuberance

- inferior nuchal line is less distinct than superior nuchal line

foramen magnum, hypoglossal canal

what are the foramen of the occipital aspect of cranium

foramen magnum

passage for medulla, vertebral arteries, spinal roots of CN XI, meninges

hypoglossal canal

passage for hypoglossal nerve

articulates with C1

the condyles of the occipital part of the cranium

lambda

junction of the sagittal and lambdoid sutures

vertex

superior most point of the cranium, near midpoint of sagittal suture

bregma

region where sagittal suture intersects the coronal suture

anterior fossa

formed by frontal bone, ethmoid bone, and lesser wings of sphenoid bone

- fossa for inferior portion of frontal lobes

middle fossa

formed by sphenoid and temporal bones

- fossa for inferior portion of temporal lobes

posterior fossa

formed by temporal and occipital bones

- fossa for cerebellar region

ethmoid bone

articulates with frontal, sphenoid, vomer, nasal, maxilla, palatine and inferior nasal conchaee bones

cribriform plate of ethmoid bone

horizontal, perforated plate forming part of the roof of the nasal cavity and the floor of teh anterior cranial fossa

- contains numerous foramina for olfactory nerve (CN 1) fibers as they pass from the nasal mucosa to the olfactory bulb

crista galli

attachment for the falx cerebri (dural fold that separates the cerebral hemispheres)

perpendicular plate

vertical plate - superior part of the nasal septum

- articulates with the vomer and septal cartilage

ethmoid air cells

small, interconnected air-filled sinuses

orbital plate

forms majority of the medial orbital wall

superior and middle nasal conchae

curved bony shelves projecting into the lateral nasal wall

- increase surface area for air filtration, warming, and humidification

sutures

fibrous joints (synarthroses) connecting the bones of the skull

- allow for brain growth as well as neurocranial and viscerocranial growth in childhood

- become more rigid with age

coronal suture

joins frontal to left and right parietal bone

sagittal suture

joins left and right parietal bone

lambdoid suture

joins the left and right parietal bones to occipital bone

squamosal suture

joins parietal and temporal bones

bregma

region where sagittal suture intersects the coronal suture

- in infants it is the "soft spot" (Anterior fontanelle)

anterior fontanelle

membranous, diamond shaped gap between frontal and parietal bones

- allows for rapid brain growth and cranial deformity during vaginal births

- closes around 12-18 months of age

pterion

region where parietal, frontal, temporal, and sphenoid bones (middle meningeal artery is close to this area so blows in this region can tear the artery causing an epidural hematoma)

lambda

region where sagittal suture intersects the occipital suture

vertex

superior most point of the cranium, near midpoint of sagittal suture