Cranial nerves & Cranial nerve nuclei
Superficial attachements of Cranial nerves :
OLFACTORY
Optic
Oculomotor & trochlear Nerves
Nerves : III : Oculomotor N.
Eye movements brought about by the extraocular muscles :
T.S of midbrain at the level of sup.colliculus
light reflex.
to illustrate the pathway of pupillary
Accomodation Reflex :
IV : Trochlear Nerve :
VI : Abducens Nerve :
Lesions of cranial nerves III,IV and VI :
V : Trigeminal Nerve :
V : Sensory components
of Trigeminal Nerve :
Sensory components of Trigeminal nerve
(for touch/pressure & pain/temperature) :
Sensory components of Trigeminal nerve
(for proprioceptive sensation):
Lesions of Trigeminal Nerve :
Herpes Zoster infection of sensory root of trigeminal N. ….. Leads to severe stabbing pain & eruption
of vesicles localised to skin supplied by its branches : ophthalmic , or maxillary or mandibular N…..
Trigeminal Neuralgia.
Syringo-bulbia ,it is a disease of unknown etiology which affects the closed M.O, causes central
cavitation of medulla caudal to 4th V. , leading to destruction & damage of decussating trigeminothalamic Fs., causing selective loss of pain & temp. sensation in the face
(
dissociated sensory loss), mostly leading to destruction of the cervical spinal cord (syringomyelia)
=cavitation of spinal cord.
VII : Facial Nerve :
VII : Facial Nerve :
VII : Facial Nerve :
VII : Facial Nerve :
Bell’s Palsy :LMN facial paralysis
It is due to acute unilateral inflammation of facial nerve within the skull (in facial canal).
 Manifested by paralysis of facial muscles of upper & lower parts of face on the same side of
lesion..

Manifested by pain around ear , - failure to close eye, absent corneal reflex, - loss of taste
sensation in anterior 2/3 of tongue, & hyperacusis =increased sound perception due to
paralysis of stapedius.
(action of stapedius = damping down the intensity of high
pitched sounds by damping down movement of stapes)

If herpes zoster virus is the inflammatory agent ,
a vesicular rash appear in ext.
auditory canal & m.m of oropharynx (Ramsay Hunt syndrome).
VIII : Vestibulocochlear Nerve :
VIII : Vestibular Nerve :
Vestibular Nerve Fibres :
Vestibular Nerve Fibres :
Lateral aspect of cerebral hemisphere
Lateral aspect of cerebral hemisphere
Acoustic Neuroma :
It is a benign tumour of vestibulocochlear nerve leads to compression of the nerve & adjacent
structures in cerebello-pontine angle.
So, there is attacks of dizziness & deafness.
With expansion of tumour, ataxia (disturbances of voluntary movement) & paralysis of cranial
Ns.(especially V-VII) and the limbs follow due to damage of pyramidal Fs.
IX : Glossopharyngeal Nerve :
IX : Glossopharyngeal Nerve Fibres :
IX : Glossopharyngeal Nerve Fibres :
X : Vagus Nerve :
X : Vagus Nerve Fibres :
XI :Accessory Nerve :
XII : Hypoglossal Nerve :
Motor neurone disease and lesions of cranial nerves IX-XII :
Occures in those over 50 years due to chronic degeneration of cortico-bulbar tracts projecting to
nucleus ambiguus (sends motor Fs.in 9,10,11 nerves) & hypoglossal nucleus , leading to dysphonia
(difficulty in phonation), dysphagia (difficulty in swallowing) , dysarthria ( difficulty in articulation)
and weakness & spasticity of tongue (pseudobulbar palsy).
There is also degeneration of nucleus ambiguus & hypoglossal nucleus themselves, leading to
dysphonia,dysphagia, dysarthria and weakness, wasting & fasciculation of tongue (bulbar palsy).
IX-XII nerves can be damaged by tumours in skull foramina, lead to dysphonia, weakness, wasting &
fasciculation of tongue and depression of gag reflex + wasting of sternomastoid & trapezius Ms.