Cranial fossa and nerves Flashcards
what lobes of the brain is found in the anterior fossa
frontal lobes
what feature can be seen inside the frontal bone but is not part of the cranial fossa
frontal air sinus
why is the frontal air sinus not considered within the cranial fossa
it lies within the frontal bone not inside the skull cavity
what is the name of the bony ridge formed by the frontal bone that provides attachment for the dura mater
crista gali
the cribriform plate is part of the _____ bone
ethmoid
why lies of the superior surface of the cribriform plate
olfactory bulbs
describe the path of the olfactory nerves
project up from nasal cavity through the cribriform plate to join the olfactory bulb (CN I)
what bone other than the frontal contributes to the anterior fossa of the skull
sphenoid bone
what bone contains the optic canals
sphenoid bone
the optic canals allow what to pass between the orbit and the inside of the skull
optic nerves (CN II) and the ophthalmic artery
what bone forms the orbital fissures
sphenoid bone
what foramina are found in the sphenoid bone
orbital fissures
foramen rotundum
foramen ovale
foramen spinosum
what nervous structure sits on the floor of the middle cranial fossa
trigeminal nerve forms a large ganglia that sits on the floor of the middle cranial fossa
what are the 3 divisions of the trigeminal nerve
ophthalmic (CNV1)
maxillary (CNV2)
mandibular (CNV3)
V1 is what modality
sensory
V1 passes through what cranial fossa to reach the orbit
superior orbital fissure
V2 is what modality
sensory
V2 passes through what foramen to pass towards the maxilla
foramen rotundum
V3 is what modality
motor and sensory
V3 goes through what foramen to reach where
foramen ovale to reach the infratemporal fossa
what nervous structures pass through the foramen ovale
otic ganglion
CN V3
lesser petrosal nerve
where exactly does the otic ganglion sit
sits at the exit of the foramen ovale in the infratemporal fossa
what structures pass through the foramen ovale
otic ganglion CN V3 accessory meningeal artery lesser petrosal nerve emissary veins
what artery is found in the foramen ovale
accessory meningeal artery
the foramen spinosum carries what artery
middle meningeal artery
the middle meningeal artery is a branch of what
maxillary artery
the middle meningeal artery supplies blood where
dura
what foramen allows the internal carotid artery to enter the middle cranial fossa
foramen lacerum
what artery is found in the foramen lacerum
internal carotid artery
what lobes of the brain lie in the middle cranial fossa
temporal lobes
what foramen are found in the middle cranial fossa
foramen rotundum
foramen ovale
foramen lacerum
foramen spinosum
the internal carotid artery enters the skull via what canal
carotid canal
the internal carotid artery enters the skull via the carotid canal then does what
turns away from the canal and enters the top of the foramen lacerum
describe the path of the internal carotid artery upon entering the foramen lacerum
does not pass all of the way through the foramen lacerum (small blood vessels traverse the length)
the internal carotid artery does not pass all of the way through the foramen lacerum. It then lies either side of the body of what bone
sphenoid bone
the internal carotid artery lies either side of the body of the sphenoid bone where it will enter the _____ before contributing to the ____
cavernous sinus
circle of willis
describe the path of the internal carotid artery in the head
enters the skull via the carotid canal
turns and enters the top of the foramen lacerum
does not pass all of the way through the foramen lacerum (small blood vessels traverse the length of the foramen lacerum)
Then lies either side of the body of the sphenoid bone where it will enter the cavernous venous sinus before contributing to the circle of Willis
what bone contributes to the floor of both the middle and posterior cranial fossa
temporal bone
what bone forms most of the floor of the posterior cranial fossa
occipital bone
the posterior cranial fossa borders what foramina
jugular foramen
foramen magnum
the posterior cranial fossa forms what canals
hypoglossal canals
the jugular foramen is the starting point of what
internal jugular cein
the jugular foramen allows what structures to pass
internal jugular vein
glossopharyngeal nerve
vagus nerve
accessory nerve
the foramen magnum allows the passes of what
start of the spinal cord and its meninges
vertebral arteries
spinal part of the accessory nerve
the hypogossal canal allows what to exit the skull
hypoglossal nerve
where does the cerebellum lie
posterior cranial fossa
the jugular foramen is between what 2 bones
occipital and temporal
in the posterior cranial fossa there is a groove for what
sigmoid dural venous sinus
the foramen magnum is in what bone
occipital
the hypoglossal canals are in what bone
occipital
the optic canal is in what bone
sphenoid
the foramen ovale is in what bone
sphenoid
the foramen rotundum is in what bone
sphenoid
where does the internal acoustic (auditory) meatus sit
petrous part of the temporal bone
the internal acoustic meatus allows what to exit the cranial cavity and enter the temporal bone
facial nerve and the vestibulocochlear nerve
name the cranial nerves
I - olfactory II - optic III - oculomotor IV - trochlear V - trigeminal VI - abducent VII - facial VIII - vestibulocochlear IX - accessory X - vagus XI - glossopharyneal XII - hypoglossa
what nerve provides the sense of smell
olfactory
what part of the olfactory nerve is seen on the surface of the brain
olfactory bulb and tract - not the nerves themselves
describe the path of the olfactory nerve
passes from the mucosa in the nose through the cribriform plate to synapse in the olfactory bulb
the olfactory nerve is an outgrowth of what
telencephalon
the olfactory tracts go from the olfactory bulb to where
prepiriform area of amygdala (primary olfactory cortex)
where is the primary olfactory cortex
prepiriform area of amygdala
the olfactory nerve is the only sensory system that is not relayed through the
thalamus
the optic nerves form a ____ where fibres from each eye will cross to the other side of the brain
optic chiasm
where do the optic tracts run
optic chiasm to other areas of the brain (lateral geniculate body of thalamus) then striate area (visual cortex)
where do fibres of the optic tract run from the thalamus
occipital lobe to be processes in the visual cortex
where is the visual cortex
occipital bone
the optic nerve is an extension of what
diencephalon
describe the route of the optic nerves
retina through the optic canal to form a chiasm then optic tracts
90% of fibres of the optic nerves go to the ______ of the thalamus
lateral geniculate body of the thalamus
fibres of the optic tract run from the lateral geniculate body of the thalamus to the
striate area (visual cortex)
describe the route of 10% of optic nerve fibres
along medial route (non-geniculate) - unconscious regulation
what 2 cranial nerves arise from the midbrain
oculomotor
trochlear
the oculomotor nerve arises from
the midbrain
the oculomotor nerve runs from the midbrain through what fissure to where
superior orbital fissure to orbit
where do the oculomotor nerves run in the cranial cavity
run in lateral wall of cavernous dural venous sinus
the oculomotor nerve has important innervation of what
extra-ocular muscles and changes to shape of lens and pupil
where do the recti muscles of the eye attach
annular ring (ring of Zinn)
where is the annular ring (ring of Zinn) found
posterior part of the orbit
what fibres does the oculomotor nerve carry
somatic motor and parasympathetic (visceral efferent)
the oculomotor nerve supplies motor innervation to what recti of the eye
inferior oblique superior rectus inferior rectus medial rectus levator palpabrae AO3
the oculomotor nerve supplies parasympathetic innervation to
sphincter pupillae and ciliary muscle
the superior division of the oculomotor nerve supplies innervation to what
levator palpabrae and superior rectus
what fibres does the trochlear nerve carry
motor
what does the trochlear nerve innervate
superior oblique
SO4
the trochlear nerve arises from where
midbrain
the trochlear nerve passes through what foramen to the orbit
superior orbital fissure
the trochlear nerves run where in the cranial cavity
run in lateral wall of cavernous dural venous sinus
does the trochlear nerve pass through the annular ring
no, outside it
what 2 facts about the trochlear nerve make it unique from the other cranial nerves
- only cranial nerve in which all fibres cross to the opposite side
- only cranial nerve from the posterior surface of the midbrain so longest intracranial course of the cranial nerves
the trigeminal nerve originates from where
pons
CNV1 goes through what fossa
superior orbital fissure
CNV2 goes though what fossa
pterygopalatine fossa
CNV3 goes through what fossa
foramen ovale to inferior surface of base of skull
what modality it CNV
motor and sensory
what nerves allow passage of parasympathetic fibres from other cranial nerves
Lacrimal (CNV1)
Zygomatic (CNV2)
lingual and auriculotemporal (CNV3)
the trigeminal nerves supplies motor and sensory to what
motor to muscles of mastication
sensory to face
CNV1 provides general sensory to what
eye lacrimal gland eyebrow skin of forehead nose
CNV3 runs where in cranial cavity
lateral wall of cavernous dural venous sinus
CN V2 supplies general sensory to what
skin of cheek lower eyelid upper jaw and teeth side of nose mucosa of mouth
CNV2 runs where in cranial cavity
lateral wall of cavernous dural venous sinus
CNV3 gives general sensory to where
ear canal
parotid gland
lower jaw and teeth
anterior 2/3 of tongue
CNV3 gives motor to where
muscles of mastication anterior belly of digastric mylohyoid tensor tympani veli tensor tympani
where is tensor tympani found
small muscle in middle ear that attaches to the malleus
what is the function of tensor tympani
attaches to malleus (ossicle) and dampens vibrations from the tympanic membrane to prevent damage to inner ear structures
what is the function of tensor veli palatini
tense soft palate
what supplies motor innervation tensor tympani and tensor veli palatini
CNV3
the abducent nerve originates from
pons
the abducent nerve passes through what foramen to reach the orbit
superior orbital fissure
what is the function of the abducent nerve
motor to lateral rectus
LR6
what is the pneumonic to remembering innervation of extraocular muscles
SO4 LR6 AO3
the abducent nerve passes through the cavernous dural venous sinus with what
internal carotid artery
does the abducent nerve pass through the annular ring
yes
the abducent has a short/long extra dural pathway
long
what cranial nerve runs through the middle of the cavernous venous sinus
CN VI (Abducent)
what nerves pass in the lateral walls of the cavernous venous sinus
III, IV, V
CN VI runs through the middle of the cavernous venous sinus with what
internal carotid artery
the cavernous venous sinus surrounds what structure of the brain
pituitary gland
the pituitary gland is found in what fossa
hypophysial fossa
what sinus is below the pituitary gland
sphenoidal sinus
the facial nerve originates from where
pons
the facial nerve passes through which foramen to reach what bone
internal acoustic meatus
temporal bone
what muscle does the facial nerve supply in the petrous part of the temporal bone
stapedius
what is the function of stapedius
small muscle that attaches to the stapes (an ossicle) and dampens its movement at the oval window to prevent damage to the inner ear
what branches of the facial nerve carry parasympathetic secretomotor fibres
the greater petrosal and chorda tympani
how do the greater petrosal and teh chorda tympani deliver parasympathetic secretomotor innervation
join parts of the trigeminal nerve
the greater petrosal nerve supplies parasympathetic secretomotor fibres to what
lacrimal gland
the chorda tympani supplies parasympathetic secretomotor fibres to what
sublingual and submandibular salivary glands
the facial nerve supplies motor innervation to what
muscles of facial expression
stapedius
stylohyoid
posterior belly of digastric
motor fibres to muscles of facial expression go through what foramen
stylomastoid foramen
what are the motor branches of the facial nerve
temporal zygomatic buccal mandibular cervical posterior auricular
the facial nerve carries sensory innervation to what
parts of auricle
special sensory to the anterior 2/3 of the tongue
what supplies the anterior 2/3 tongue
special sensory - facial nerve
CNV3 - general
the vestibulocochlear nerve has what parts
vestibular parts - balance
cochlear parts - hearing
what modality is the vestibulocochlear nerve
special somatic afferent
the vestibular and auditory apparatus go through what foramen to where
internal auditory meatus to pons/medulla oblongata
what other areas of the brain does the vestibular part of the vestibulocochlear nerve involve
cerebellum
CN III, IV, VI
spinal tracts
what other areas of the brain does the cochlear part of the vestibulocochlear nerve involve
inferior colliculi
medial geniculate nucleus of the thalamus to auditory cortex (area 41 temporal)
where does the glossopharyngeal nerve originate
medulla oblongata
what foramen does the glossopharyngeal nerve pass through
jugular foramen
the glossopharyngeal nerve provides parasympathetic innervation to what
parotid gland
buccal and labial glands
the glossopharyngeal nerve supples taste to what
posterior 1/3 tongue
the glossopharyngeal nerve supplies motor to what
pharyngeal plexus and stylopharyngeus
the glossopharyngeal nerve supplies sensory innervation to where
posterior 1/3 tongue soft palate pharynx tympanic cavity and membrane pharyngotympanic tube external ear auditory canal
what nerve is responsible for the gag reflex
glossopharyngeal
how does the glossopharyngeal nerve supply parasympathetic innervation to the parotid gland
communicates via the lesser petrosal nerve with the auriculotemporal branch of the trigeminal nerve
the glossopharyngeal does what at the bifurcation of the common carotids
senses changes in pressure
where does the vagus nerve originate
medulla oblongata
the vagus nerve passes through which foramen
jugular foramen
what modality is the vagus nerve
sensory
motor
parasympathetic
the parasympathetic fibres of the vagus nerve join what to supply what
oesophageal, cardiac, bronchial plexi in the thorax and supply parasympathetic innervation up to 2/3 along transverse colon
what does the vagus nerve supply motor innervation to
pharyngeal plexus
soft palate
larynx
the vagus nerve provides sensory innervation where
dura in posterior cranial fossa ear external auditory canal lower pharynx laryngeal mucosa thoracic and abdominal viscera
the recurrent laryngeal branch wraps around what on the left
aortic arch
the recurrent laryngeal branch wraps around what on the right
subclavian artery
the recurrent laryngeal nerves ascend the neck between what
oesophagus and trachea
the recurrent laryngeal branches supply what
intrinsic muscles of the pharynx
the vagus nerve joins the _____ plexus which forms the motor part of the ___ reflex
pharyngeal plexus
motor part of gag reflex
what is the sensory part of the gag reflex
glossopharyngeal
what is the motor part of the gag reflex
vagus nerve
what receptors are found in the aortic arch
pressure
what receptors are found in the para-aortic body
chemoreceptors
the spinal accessory nerve originates where
spinal cord
the spinal accessory nerve passes through what foramen
foramen magnum to join cranial root then passes through jugular foramen
the spinal accessory nerve supplies motor to
trapezius and sternocleidomastoid
the cranial root is now considered part of what nerve
vagus nerve (soft palate)
what modality is the spinal accessory nerve
motor
the spinal accessory nerve crosses where in the neck
posterior triangle
why is the spinal accessory nerve said to have 2 parts
spinal part that comes from the top of the spinal cord, passes into the skull via the foramen magnum and joins cranial roots from the medulla. The final accessory nerve then passes back out of the skull via the jugular foramen
what supplies innervation to the muscles of the soft palate
cranial part of accessory / vagus nerve
CN IX, X and XI all originate from posterior lump on the surface of the medulla called the
olive (one each side of midline)
the hypoglossal nerve originates from where
medulla oblongata (anterior to olive)
what is the only cranial nerve to emerge from the medulla anterior to the olives
hypoglossal nerve
the hypoglossal nerve supplies motor to what
most of musculature of the tongue - all intrinsic muscles and all extrinsic muscles except palatoglossus
the hypoglossal nerve passes through what foramen
hypoglossal canal
the hypoglossal nerve enters root of the tongue below/above hyoid bone
above