Cranial Nerves Flashcards
What fibre type does the Olfactory Nerve carry?
SVA - smell
What is the olfactory tract/bulb?
The olfactory tract is the structure which runs along the inferior surface of the frontal lobe, the olfactory bulb is a swelling at the end of this where 1st order neurones synapse with 2nd order neurones.
Where does CN I originate?
It is an extension of forebrain,
What fibre types are carried by the optic nerve?
SSA - special sense (vision) not associated with viscera.
What fibre types does the Occulomotor nerve have?
GSE to muscles
GVE to autonomically supplied muscles
Describe the origin of partial ptosis.
The eye lid is supplied by levator palpebrae Superioris - innervated by CN III however a small part called the superior tarsal muscle is innervated by sympathetic fibres, if innervation is lost to this structure then partial ptosis occurs,
Through which structures does the Occulomotor nerve pass on its route to the orbit?
Cavernous sinus and medial aspect of superior orbital fissure.
Which nerve originates from the dorsal aspect of the brainstem?
Trochlea nerve
What fibres are carried by the trochlea nerve?
GSE to Superior oblique
What fibres are carried by the Abducens nerve?
GSE to lateral rectus
Where in the superior orbital fissure do Nerves to the orbit run?
Medial - Occulomotor, Abducens, nasocilliary
Lateral - frontal, trochlea, lacrimal
Where does the Abducens nerve originate?
From the pontomedullary junction.
What true trigeminal fibres run in the trigeminal nerve?
SVE to muscles of mastication
GSA to face and scalp
What structures are supplied by facial nerve fibres? What fibre types supply these?
SVA - taste to anterior 1/3 of the tongue
SVE - muscles of facial expression
GVE - submandibular/ sublingual salivary glands, accessory palatine salivary glands, nasal glands and lacrimal glands
Where are the cell bodies of sensory fibres of the facial nerve located?
Geniculate ganglion in the petrous part of the temporal bone.
Where does the facial nerve exit the cranial cavity?
Internal acoustic meatus
Besides the muscles of facial expression, which other muscles are supplied by the facial nerve?
Stapedius, posterior belly of digastric, stylohyoid.
What fibres run in the vestibulocochlear nerve?
SSA - Auditory
Describe the course of the vestibulocochlear nerve.
This nerve emerges from the cerebllopontine angle and runs laterally into the internal acoustic meatus. In the lateral aspect of this meatus it divides into 2 Nerves - vestibular and cochlea.
How many fibre types does the glossopharyngeal nerve contain?
5 SVA to posterior tongue GSA to posterior tongue, pharynx and ear SVE to stylopharyngeus GVE to parotid gland GVA to carotid body and sinus
Which nerve supplies stylopharyngeus? What is the fibre type?
Glossopharyngeal
SVE
Which nerve supplies the carotid body and sinus?
Glossopharyngeal
GVA
How does the glossopharyngeal nerve exit the cranial cavity?
Through the jugular foramen
What are the main structures supplied by the vagus nerve?
Motor to the muscles of pharynx and larynx, sensory supply to external acoustic meatus, taste to vallecula and epiglottis, parasympathetic supply to thorax and abdomen and visceral sensation to thorax and abdomen,
What fibre types are contained in the vagus nerve and what do these supply?
GVA - stretch to larynx and chemoception/ stretch to thorax and abdomen
SVA to vallecula and epiglottis
SVE - muscles of the larynx and pharynx
GVE - parasympathetic supply to thorax/abdomen
GSA - dura and External acoustic meatus
Which structures are supplied by SVE fibres of CN X?
Muscles of pharynx and larynx, palatoglossus, levator veli palatini
With what structures in the neck does the vagus nerve run?
Runs within the carotid sheath with the internal jugular vein and the internal carotid artery.
How does CN X exit the cranial cavity?
Via the jugular foramen
Where in the brainstem does the vagus nerve arise?
Dorsolateral sulcus of the medulla
Describe innervation of the SCM and Trapezius muscles.
These muscles receive the majority of their motor supply from the accessory nerve however there is some debate as to whether cervical plexus fibres contribute to this.
Proprioception supply to these muscles is by the cervical plexus.
What fibres are contained within the accessory nerve?.
SVE to SCM and Trapezius
Describe the course of the the spinal part of the accessory nerve.
This originates from the cervical spine and passes into the cranial cavity via foramen magnum and joins with the cranial part of the nerve. This then e it’s the cranial cavity through the jugular foramen.
What does the hypoglossal nerve supply?
Motor to muscles of the tongue. GSE fibres.
Where does the hypoglossal nerve arise?
Anteriorlateral aspect of the medulla.
Where does the hypoglossal nerve exit the cranial cavity?
Hypoglossal canal found on the lateral aspect of foramen magnum.
Which nerves contain SVA?
I, VII, IX, X
Which nerves contain SSA?
II, VIII
Which nerves contain GSA?
V, VII, IX, X
Which nerves contain GVA?
VII, IX, X
Which nerves contain a SVE?
V, VII, IX, X
Which nerves contain GSE?
III, IV, VI, XII
Which nerves contain GVE?
III, VII, IX, X
