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



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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 to illustrate the pathway of pupillary light reflex.

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 trigemino-thalamic 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.


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