Cranial nerves function Flashcards
Function of Olfactory nerve?
Special sense of smell
Where does Cr.N I exit the skull?
Cribriform plate of the ethmoid bone.
What is the function of Cr.N II?
The optic nerve is responsible for vision.
Where does the Optic nerve exit the skull?
Cr.N II exits through the optic canal
What three nerves contribute to eye movement?
Cr.N III- oculomotor (innervates all but two of the extra-ocular eye muscles)
Cr.N IV- trochlear, this innervates the superior oblique muscle and is therefore responsible for a down and outwards movement.
Cr.N VI- abducens innervates the lateral rectus muscle, this is responsible for the abduction of the eye.
Which nerves exit the skull through the superior orbital fissure?
Oculomotor - III
Trochlear- IV
Ophthalmic branch of the trigeminal - V1
Abducens - VI
What is the function of the Trigeminal nerve?
It is the sensory supply to the face through its three branches (including the ophthalmic branch being the sensory innervation for the eye).
It also supplies motor function to the muscles of mastication.
What is the function of Cr.N VII?
The facial nerve supplies the muscles of facial expression. It also innervates special sense of taste from the anterior 2/3 of the tongue and supplies the submandibular and sublingual glands.
Where does the Maxillary branch of the Trigeminal leave the skull?
The foramen rotundum
Where does Cr.N V3 exit?
The foramen ovale.
Where does the Facial nerve leave the skull?
Cr.N VII exits via the internal auditory meatus and then through the facial canal in the temporal bone and out of the stylomastoid foramen.
Facial supplies general sense in the ear.
The vestibulocochlear also exits via the internal auditory meatus.
What is Cr.N VIII?
Vestibulocochlear nerve.
What nerves are responsible for movement of the pharyngeal muscles?
The Glossopharyngeal - Cr.N IX
Vagus nerve- Cr.N X
The glossopharyngeal is also special sensory from the posterior 1/3 tongue.And general sensory from the ear.
Which nerves leave through Jugular foramen?
Glossopharyngeal - Cr.N IX
Vagus- Cr.N X
Accessory- Cr.N XI
Where does Cr.N XII exit the skull?
The hypoglossal nerve leaves through the hypoglossal canal.
What is the function of the accessory nerve?
It innervates the sternocleidomastoid muscle and the trapezius muscle.
What is the function of the hypoglossal nerve?
It supplies motor innervation to the tongue.
What causes pupillary constriction?
Oculomotor - Cr.N III
What innervates the parotid gland?
Cr. N IX- glossopharyneal, this stimulates salivation
What innervates salivation on the submandibular and sublingual glands?
Cr.N VII - facial nerve
What near is lacrimation innervated by?
The facial nerve- Cr.N VII
Where are the nuclei of cranial nerves III and IV?
They are in the midbrain
Which cranial nerves have their nuclei in the Pons?
V-trigeminal
VI-abducens
VII- facial
Where is the nuclei of the vestibulocochlear nerve?
Nuclei of the VIII nerve is at the Ponto-medullary junction
Which nerves have their nuclei in the Medulla?
IX- Glossopharyngeal
X- vagus
XI- Accessory
XII- Hypoglossal
What is Bell’s palsy?
Idiopathic paralysis of the facial nerve.
How do you treat Bell’s palsy?
Steroids and sometimes aciclovir
What are the symptoms of vestibular neuronitis?
Sudden onset
Disabling vertigo
Vomiting
Gradual recovery
What is the difference between Bulbar palsy and pseudobulbar palsy?
Bulbar palsy is a LMN problem
and Pseudobulbar palsy is an UMN problem.
What is pseudobulbar palsy and it’s symptoms?
Bilateral UMN lesions e.g. in vascular lesions of both internal capsules
- dysarthria
- dysphonia (problem with volume of speech/hoarsness)
- dysphagia
- spastic, immobile tongue
- brisk jaw jerk
- brisk gag reflex
What is bulbar palsy and what are it’s symptoms?
Bilateral LMN lesions affecting IX - XII
- wasted, fasciculating tongue
- dysarthria
- dysphonia
- dysphagia
