Cranial Foramina Flashcards
cranial base is the ___ and has 2 surfaces which are ______ and _____
floor of cranial cavity
2 surfaces: endocranium and external cranial base
external cranial base involves
viscerocranium and neurocranium
endocranium
is the ____ surface of cranial cavity
composed of which fossa?
internal surface of cranial cavity base
3 cranial fossae: anterior, middle, & posterior (PAM)
foramen
small opening in bone to allows passage of structure in/out of cranial cavity
fissure
openings not entirely surrounded by bone structure
canals
openings larger in length than diameter (long and skinny)
anterior fossa
location
contains what 2 structures
located superior to orbital and nasal fossa
contains frontal lobes and olfactory bulb
what are the 2 foramina of the anterior fossa?
foramen caecum and cribiform plate
foramen caecum
articulates with ___ bone
contains what major vein
what is its clinical relevance
articulates with ethmoid bone
contains emissary vein from nose to superior sagittal sinus
clinical relevance: danger triangle of face –> nose infection can spread retrograde facilitated by emissary vein
risks: sinus thrombosis, abscesses, & meningitis
cribiform plate
separates which 2 cavities
supports _____
contains what major structure
what foramina does it contain and what does it allow passage for
separates nasal and cranial cavities
supports olfactory bulb
contains crista galli (part of ethmoid bone)
olfactory foramina = passage for olfactory fibers
middle cranial fossa contains what 2 major structures
temporal lobes and pituitary gland (body sphenoid bone contains pituitary gland too)
list the 7 foramina that the middle cranial fossa contains
- optic canal
- superioir orbital fissure
- foramen ovale
- foramen rotundum
- foramen spinosum
- foramen lacerum
- foramen petrosum
optical canal
location
connects which 2 cavities
allows passage of (2)
how are the optic canals connected
location: sphenoid bone
connects orbital and cranial cavities
passage of: optic nerve & opthalmic artery
optic canals connect by chiasmatic sulcus on ea. side of skull
superior orbital fissure
located between what structures
passage for which structures (5)
cleft between lesser and greater sphenoid bone
opens into orbital cavity
passage for:
1. Oculomotor nerve (CN3)
2. Trochlear nerve (CN4)
3. Trigeminal nerve (CN5) - (opthalmic branch)
4. Abducens nerve (CN6)
5. Opthalmic veins
foramen rotundum
location
connects what 2 structures
allows passage for
round opening
location: sphenoid bone
connects pterygopalatine with middle cranial fossa
passage for: maxillary branch of trigeminal nerve (CN5)
foramen ovale
location
opens into _____ fossa
passage for which CN?
largest foramina in cranial base
location: greater wings of posterior sphenoid
opens into infratemporal fossa
passage for: mandibular brach of trigeminal nerve (CN5)
foramen vesalii
aka:
location
aka: sphenoidal emissary foramen
location: greater wing of sphenoid
foramen spinosum
location
allows passage for (3)
location: greater wing of sphenoid
passage for: middle meningeal artery, middle meningeal vein, meningeal branch of mandibular nerve (CN5)
carotid canal
passes through ___ (bone)
connects ____ with ____
passed for ___ artery and ____ nerve
passes through temporal bone
connects neck with middle cranial fossa
passage for: carotid artery and petrosal nerve
foramen lacerum
shape of this opening
after birth what change does it undergo
which nerve is present here
triangular opening
filled with cartilaginous tissue after birth
houses petrosal nerve
foramen petrosum
location
found between which 2 foramina
passage for ____
location: greater wing of sphenoid
found between foramen spinosum and ovale
passage for: petrosal nerve
posterior cranial fossa
location/depth
supports what 2 major structures
Composed of which 3 bones
posterior and deepest depression of cranial cavity
supports brainstem and cerebellum
composed of: temporal bones, occipital bone, and small portion of parietal bones
foramina of posterior cranial fossa (4)
internal acoustic meatus
foramen magnum
jugular foramina
hypoglossal canal
internal acoustic meatus
what region of temporal bone is it located
connects ____ with _____
passage for: (4)
canal on petrous region of temporal bone
connects inner ear with posterior cranial fossa
passage for: facial nerve (CN7) , vestibulocochlear nerve (CN8), labyrinthe artery, & vestibular ganglion
foramen magnum
location
passage for (5)
location: occipital bone
passage for: medulla oblongata, meninges, spinal cord accessory nerve, anterior/posterior spinal carties, & vertebral arteries
clinical relevance of conditions associated with foramen magnum
conditions like congenital structure defects or increased intracranial pressure from conditions like hydrocephalus can cause herniation of cerebellar tonsils through foramen magnum. this results in compression of vital structures like the pons and medulla oblongata
jugular foramen
located between which 2 bones
allows passage for what structures (6)
large foramen between temporal bone and occipital bone
passage for:
1. glossopharyngeal nerve (CN 9)
2. Vagus nerve (CN 10)
3. Spinal accessory nerve (CN 11)
4. Inferior jugular vein
5. inferior petrosal sinus
6. sigmoid sinus
hypoglossal canal
location
allows passage for (1)
location: occipital bone
passage for: hypoglossal nerve (CN 12)
mastoid foramen
location
allows passage for (2)
location: temporal bone
passage for:
1. mastoid emissary vein to sigmoid sinus
2. small branch of occipital artery to dura mater
The vestibulocochlear nerve passes through the posterior cranial fossa. What provides passage of this structure?
internal acoustic meatus
Olfactory axons of cranial nerve I pass through the anterior cranial fossa. What provides passage of this structure?
Cribiform plate
A fissure exists between the anterior and middle cranial fossa. Which structure within this fissure is most inferior?
abducens nerve
The greater petrosal nerve passes through the middle cranial fossa. What provides passage of this structure?
foramen lacerum
