Cranial nerves Flashcards
How many cranial nerves are there?
12 pairs
What do parasympathetic nerves innervate?
Glands, smooth muscle
Is there any sympathetic outflow from the skull?
No
What nerve fibres are present in olfactory nerve?
Special sensory
What nerve fibres are present in optic nerve?
Special sensory
What nerve fibres are present in oculomotor nerve?
Motor
Parasympathetic
What nerve fibres are present in trochlear nerve?
Motor
What nerve fibres are present in trigeminal nerve?
Motor
Sensory
What nerve fibres are present in abducens nerve?
Motor
What nerve fibres are present in facial nerve?
Motor
Sensory
Parasympathic
What nerve fibres are present in vestibulocochlear nerve?
Special sensory
What nerve fibres are present in glossopharyngeal nerve?
Sensory
Motor
Parasympathetic
What nerve fibres are present in vagus nerve?
Sensory
Motor
Parasympathetic
What nerve fibres are present in spinal accessory nerve?
Motor
What nerve fibres are present in hypoglossal nerve?
Motor
Where does the olfactory nerve fibres pass through the skull?
Cribiform plate of ethmoid
What is the name for lost sense of smell?
Anosmia
An increase in ICP can result in which eye condition?
Papillodema
A lesion at the optic chiasm will result in what type of visual field loss?
Bitemporal hemianopsia
A lesion at the right optic tract will result in what type of visual field loss?
left homonymous hemianopsia
Which foramen does the optic nerve pass through?
Optic foramen
Where do the retinal nerve fibres synapse?
Lateral geniculate body
Where does the oculomotor nerve originate?
Midbrain
Where does the oculomotor emerge from the skull?
Superior orbital fissure
What does the oculomotor supply in the eye?
Extraocular muscles & eyelid Constricts pupil (circular muscles) & accommodates lens (ciliary muscle)
If the oculomotor is lesioned, what will be observed?
Ptosis (eyelid drooping)
Eyeball abducted and pointing down
No pupillary reflex
No accommodation
Where does the trochlear nerve exit the skull?
Superior orbital fissure
What does the trochlear nerve supply?
Superior oblique (turns eye down)
What happens is the trochlear nerve is lesioned?
Diplopia (On looking down)
Where does the abducent nerve originate?
Pons
Where does the abducent nerve exit the skull?
Superior oblique fissure
What does the abducent nerve supply?
Lateral rectus muscle
If the abducens nerve is lesioned what happens?
Medial deviation of eye causing diplopia
Where does the trigeminal emerge from?
Pons
Where does the trigeminal (ophthalmic) nerve exit the skull?
Superior orbital fissure
What does V1 supply?
Sensory to cornea, forehead, scalp, eyelids & mucosa of nasal sinuses
Where does the V2 division of the trigeminal nerve exit the skull?
Foramen rotundum
What does the V2 nerve supply?
Sense to the face of maxilla, teeth, TMJ joint & mucosa of maxillary sinuses
Where does the V3 branch of trigeminal nerve exit the skull?
Foramen ovale
What does the V3 branch of the trigeminal supply?
Sense to mandible, mucosa of mouth & anterior 2/3rds of tongue
Muscles of mastication
If the trigeminal nerve is lesioned what are the clinical signs?
Paralysis of muscles of mastication
loss of corneal reflex
loss of face sensation
trigeminal neuralgia
Where does the facial nerve originate?
Pontomedullary junction
Where does the facial nerve travel?
Internal acoustic meatus and out via the stylomastoid foramen
What does the facial nerve supply?
Muscles of facial expression
Innervation of submandibular & submental salivary glands
taste to anterior 2/3rd of tongue
General sensory - external acoustic meatus
If the facial nerve is lesioned what clinical signs can be observed?
Bell’s palsy (cannot close eyelid, drooping of mouth)
What nerve is the most frequently injured?
Facial nerve
Where does the vestibulocochlear nerve originate?
Pontomedullary junction
Where does the vestibulocochlear nerve exit the skull?
Internal acoustic meatus
What are the clinical signs observed with a lesion of nerve VIII?
Tinnitus
Deafness
Vertigo
Nystagmus (involuntary rapid eye movements )
Where does the glossopharyngeal nerve originate?
Medulla
Where does the glossopharyngeal nerve exit the skull?
Jugular foramen
What does the glossopharnygeal nerve supply?
Taste posterior 1/3rd of tongue
sensation for middle ear & posterior oral cavity
innervation of parotid gland
stylopharyngeus innervation
When the glossopharyngeal nerve is lesioned, what are the clinical signs?
Loss of gag reflex & taste from back of tongue
Where does the vagus nerve exit the skull?
Jugular foramen
What does the vagus nerve supply?
Taste for epiglottis
parasympathetic innervation of pharynx, larynx, trachea, bronchi, heart & gut
Motor control to the pharynx, larynx, palate & oesophagus
What are some of the branches of vagus nerve?
Recurrent laryngeal nerve
What clinical signs will be observed if the vagus nerve is lesioned?
Difficulty swallowing
Hoarse voice
Where does the spinal accessory nerve exit the skull?
Jugular foramen
What does the spinal accessory nerve supply?
Sternocleidomastoid & trapezius
If the spinal accessory nerve is lesioned, what clinical signs will be observed?
Weakness in turning head & shrugging shoulder
Where does the hypoglossal nerve exit the skull?
Hypoglossal canal
What does the hypoglossal nerve supply?
Muscles of tongue
What clinical signs will be observed if the hypoglossal nerve is lesioned?
Deviation of tongue to affected side
Paralysis & muscle atrophy of tongue
Which nerves are required for taste?
Facial
Glossopharyngeal
Vagus
Which nerves are required for movements of face?
Facial
Which nerves are required for chewing?
V3
Which nerves are required for swallowing?
Glossopharyngeal
Accessory
Which nerves are required for movements of vocal cords?
Vagus
Which nerves have visceral sensory input?
Vagus
Glossopharyngeal (carotid body & sinus)
What are the functions of the cranial nerves?
Special senses
Ordinary sensation
Autonomic
Motor control
Which are the nerves of special sense?
I - olfaction
II - vision
XII, IX, X - taste
VIII - hearing
What nerves supply sensation to the ear?
VII & IX
Which nerve supplies muscles of mastication?
Trigeminal (mandibular branch)
Which nerve supplies muscles of facial expression?
Facial
Which nerve supplies muscles of pharynx & larynx?
Vagus
Which nerves supplies SCM & trapezuis?
Accessory spinal
Which nerves carry parasympathetic innervation?
III, VII, IX, X
What does parasympathetic activity in III nerve mediate ?
Pupillary constriction
What does parasympathetic activity in VII nerve mediate ?
Submandibular & Sublingual salivary gland
What does parasympathetic activity in IX nerve mediate ?
Parotid salivary gland
What does parasympathetic activity in X nerve mediate ?
Organs of abdomen & thorax
What nerves are involved in the pupillary reflex?
II - AFFERENT
III- Efferent
What nerves are involved in the corneal reflex?
V- Afferent
VII- efferent
What nerves are involved in the jaw jerk reflex?
V - afferent & efferent
What nerves are involved in the GAG reflex?
IX afferent
X efferent
Which cranial nerve nuclei are found in the midbrain?
III, IV
Which cranial nerve nuclei are found in the pons?
V, VI, VII
Which cranial nerve nuclei are found in the pontomedullary junction?
VIII
Which cranial nerve nuclei are found in the medulla?
IX, X, XI, XII
How can cranial nerves be damage?
Ischaemia
Crossing sub-arachnoid space (eg. meningitis)
Outside skull, eg tumours
What is the pathology behind optic neuritis? What disease is it associated with?
Demyelination of the optic nerve
MS
What are the signs of optic neuritis?
Monocular vision loss Pain on eye movement Reduced visual acuity Reduced colour vision Swelling of optic disc
What can cause dilated pupils?
Dim light Young 3rd nerve palsy "Mydriatic" eye drops Amphetamine & cocaine Brainstem death (Bilateral)
What cause pupils to constrict?
Old age Bright light Miotic eye drops Opiate overdose Horner's syndrome (sympathetic plexus)
What are the microvascular causes of 3rd nerve palsy?
What are the symptoms?
Diabetes & hypertension
Painless & pupil spared
What are the compressive causes of 3rd nerve palsy?
What are the symptoms?
Posterior communicating artery aneurysm
Raised ICP
Painful & pupil affected
What are the causes of 6th nerve palsy?
Meningitis
Raised ICP
Diabetes
Trigeminal neuralgia presents as painful attacks due to the compression of which nerve?
V
What is Bell’s Palsy?
Idiopathic facial (VII) nerve palsy
What is observed with Bell/s palsy?
Unilateral facial weakness
Inability to close eye
What are some of the LMN causes of facial nerve palsy?
Bell’s palsy
Lymes diseae
What are some of the UMN causes of facial nerve palsy?
Stroke
Tumour
What will be the signs of UMN facial palsy?
The forehead will be spared
What will be the signs of LMN facial palsy?
The whole side of the face will be affected including forehead
What are the symptoms of vestibular neuronitis?
Sudden onset of vertigo
Vomiting
Gradual recovery
What is dysarthria?
Slurred speech
Disordered articulation
What is dysphonia?
Loss of volume of speech
What is dysphagia?
Difficulty swallowing
What is the difference between bulbar palsy & pseudo bulbar palsy?
Pseudobulbar = UMN Bulbar = LMN
What is the pathology of Pseudobulbar palsy?
Bilateral vascular lesion of the internal capsule
What are some of the symptoms/ signs of pseudo bulbar palsy?
Dysarthria Dysphonia Dysphagia Spastic immobile tongue Brisk jaw & gag reflex
What nerves does bulbar palsy affect?
IX-XII
Where is the lesion in bulbar palsy?
Bilateral lesion of LMN in brainstem
What are some of the symptoms/ signs of bulbar palsy?
Dysarthria
Dysphonia
Dysphagia
Wasted, fasciulcating tongue
