Anatomy Head Flashcards
what nerve injury causes impaired tear secretion
greater petrosal nerve (from facial nerve)
Where do the cranial nerves arise from
1+2 from cerebrum Rest from brainstem 3 midbrain pontine junction 4 midbrain 5 pons 6 - 8 pontine medulla junction 8 - 11 medulla oblongata posterior to olive 12 medulla anterior to olive
What cranial nerves exit through canals
2 + 12
CN1
olfactory
CN2
optic
CN3
oculomotor
CN4
trochlear
CN5
trigeminal
CN6
abducens
CN7
facial
CN8
vestibulocochlear
CN9
glossopharyngeal
CN10
vagus
CN11
spinal accessory
CN12
hypoglossal
CN1 exit and function
cribriform plate
smell
CN2 exit and function
optic canal
vision
CN3 exit and function
superior orbital fissure
4 extrinsic eye muscles (superior, medial and inferior rectus, inferior oblique) and levator palpebrae superioris
+ pupillary sphincter (constricts pupil)
CN4 exit and function
superior orbital fissure
contralateral superior oblique muscle
CN5 exit and function
ophthalmic V1:
superior orbital fissure
sensation to scalp, forehead, cornea, nose
maxillary V2:
foramen rotundum
sensation to cheeks, lower eye lid, nasal mucosa, upper lip, upper teeth, palate
mandibular V3:
foramen ovale
sensation to anterior 2/3 tongue, skin over mandible, lower teeth, chin
+ muscles of mastication
CN6 exit and function
superior orbital fissure
lateral rectus muscle
CN7 exit and function
internal acoustic meatus > stylomastoid foramen
sensation to part of external ear + taste from anterior 2/3 tongue, hard and soft palate
+ muscles of facial expression
+ lacrimal, submandibular, sublingual glands and mucous glands of mouth and nose
CN8 exit and function
internal acoustic meatus
hearing and balance
CN9 exit and function
jugular foramen sensation to posterior 1/3 tongue, external ear, and middle ear cavity \+ carotid body and sinus \+ taste from post. 1/3 tongue \+ parotid gland, stylopharyngeus
CN10 exit and function
jugular foramen
sensation to external ear, larynx and pharynx
+ sensation from larynx, pharynx and, thoracic & abdominal viscera
+ taste from epiglottis region of tongue
+ smooth muscles of pharynx, larynx and most of the GIT, most muscles of pharynx and larynx.
CN11 exit and function
jugular foramen
trapezius and sternocleidomastoid
CN12 exit and function
hypoglossal canal
intrinsic and extrinsic tongue muscles (except the palatoglossus)
What nerve is surrounded by cranial meninges
Optic nerve
unlike other nerves surrounded by epi-, peri- and endoneurium
cavernous sinus thrombosis can cause which nerve palsy
oculomotor and abducens
they travel through the cavernous sinus
oculomotor nerve palsy features
ptosis (drooping upper eyelid)
down and out position of eye
dilated pupil
trochlear nerve palsy
diplopia
head tilt away from affected side
muscles concerned in corneal reflex
V1 of trigeminal as afferent
facial as efferent
abducens nerve palsy
affected eye resting in adduction
where does the facial nerve divide into 5 terminal branches
within parotid gland
what are the facial nerve branches
Temporal branch Zygomatic branch Buccal branch Marginal mandibular branch Cervical branch
responsible for innervating muscles of facial expression
intracranial vs extracranial lesions to facial nerve features
intracranial:
muscle of facial expression weakened or paralyzed
+ chorda tympani - reduced salivation and loss of taste on the ipsilateral 2/3 of the tongue
OR nerve to stapedius – ipsilateral hyperacusis (hypersensitive to sound)
OR greater petrosal nerve – ipsilateral reduced lacrimal fluid production
extracranial: only weakness of muscles
NB: if no cause found –> Bell’s palsy
otitis media complications
infection of middle ear
- otitis media with effusion –> glue ear, decrease in hearing
- mastoiditis –> infection of air cells
- meningitis –> when mastoiditis spreads to the middle cranial fossa and into the brain
meniere’s disease
disease of inner ear
episodes of vertigo, low-pitched tinnitus, hearing loss
excess accumulation of endolymph in membranous labyrinth –> damage thin membranes of ear that detect balance and sound
levator palpebrae superioris function and innervation
elevates the upper eyelid
oculomotor nerve
superior and inferior rectus muscles function and innervation
superior: elevates eye
inferior: moves eye downwards
both innervated by oculomotor nerve
medial and lateral rectus function and innervation
medial: adducts eye –> oculomotor nerve
lateral: abducts eye –> abducens nerve
superior and inferior oblique function and innervation
superior: down and out –> trochlear
inferior: up and out –> oculomotor
mnemonic for extraocular muscles innervation
LR6 - SO4 - R3
what are the 4 paranasal sinuses
frontal, ethmoid, sphenoid, maxillary
how does maxillary sinusitis cause toothache
maxillary nerve supplies both maxillary sinus and upper teeth
upper respiratory tract infection can spread where
- middle ear through auditory tube opening
- sinuses (continuous with nasal cavity)
- cavernous sinus thrombosis, meningitis or brain abscess (communication between cavernous sinus, facial vein, superior ophthalmic vein)
cribriform plate fracture features
- can penetrate the meningeal linings of the brain, causing leakage of CSF
- exposing brain to the outside environment increases risks of meningitis, encephalitis and cerebral abscesses
- olfactory bulb damage as it sits on cribriform plate –> anosmia
what are the salivary glands
parotid, sublingual, submandibular
what passes through parotid gland
facial nerve, retromandibular vein, external carotid artery (in gland, gives rise to posterior auricular artery, then terminates in maxillary artery and superficial temporal artery)
what is a ranula
type of mucocele (mucous cyst) that occurs in the floor of the mouth inferior to the tongue, most common disorder of sublingual glands due to their higher mucin content in secretions compared to other salivary glands
what nerves are in close relation to submandibular gland
lingual, hypoglossal, facial nerve (marginal mandibular branch)
which salivary gland is most susceptible to calculi and why
submandibular
cause: torturous length of the duct (5cm), ascending secretory pathway, nature of salivary secretion
what is the nature of each salivary gland secretion
parotid: serous
sublingual: predominantly mucous (mucin)
submandibular: mixed serous and mucous
gag reflex nerves involved
glossopharyngeal as afferent
vagus as efferent
what structures are in danger in case of TMJ dislocation
facial and auriculotemporal (from V3) nerves
All innervations of tongue
post 1/3 sensation and taste by glossopharyngeal
Ant 2/3 sensation by V3 mandibular, taste by facial chorda tympani