Brain Stem Flashcards
Ventral Brain stem
1) midbrain
- cerebral penduncles
- interpeduncular fossa (3rd CN + floor of 3rd Ventricle except optic chiasma and tegmentum)
2) Pons - CN 5th sensory (large) + motor
3) medulla
- pyramid
- olive - Inferior olivary nucleus
Cranial nerve
- b/w pons and medulla - 6
- ponto olivary junction - 7 ( motor root of 7 + nervi intermedius (nerve of wtisberg))
- lateral to 7 - 8
- lateral to olivary - 9,10,11
- between olive and pyramid - 12
Dorsal brainstem
1) midbrain : 2 superior colliculus and 2 Inferior colliculus - corpora quadrigeminal
- superior colliculus, lateral geniculate body, optic pathway
- Inferior colliculus, medial geniculate body,auditory pathway
2) pons
3) medulla
- contain nucleus involved in dorsal column/ medial lemniscus pathway. = Gracile, cuneate, inferior cerebellar penduncles.
- only nerve seen in the posterior view of brainstem - 4th cranial nerve.
Part of mid brain
1) Tectum
2) cerebral penduncles
- tegmentum
- substantia nigra
- crus Cerebri
> Medial - frontopontine
> Intermediate - Corticospinal, corticonuclear
> Lateral - parieto pontine, temporo pontine, occipito pontne
1) Mid brain at level of inferior colliculus
2) At level of superior colliculus
1) midline up to down
- mesencephalic nucleus of trigeminal
- trochlear - fiber cross inside mid brain.
- pretectal nucleus
- tectospinal track
- medial longitudinal fasiclus
- decussation of superior cerebellar penduncles
- rubrospinal track
- 4 lateral meniscus =
> lateral - auditory pathway
> spinal - spinothalamic track
> trigeminal - trigeminothalamic
> medial - dorsal column pathway
2) mesencephalic nucleus of trigeminal nerve
- oculomotor nerve
- pretectal nucleus
> Connect to interstitial nucleus of cajal - nucleus for vertical gaze.
> Optic track —⟩ afferent fibers —⟩ pretectal nucleus —> efferent to edinger wesphal nucleus —> direct and indirect light reflex.
- Dorsal tegmental decussation - tectospinal track
- red nucleus
- ventral tegmental decussation - rubrospinal track
- 4 lemniscus - medial, spinal, trigeminal.
Rule of 4
1)
4 CN in medulla - 9, 10,11,12
4 CN in pons - 5,6,7,8
2 CN in mid brain 3,4
Mid line CN - 3,4,6,12
Laterally located - 5,7,9,11
4 M - medial
- motor system - pyramid
- motor nucleus - 3,4,6,12
- medial longitudinal fasiclus
- medial lemniscus
4 S - laterally
- spinothalamic
- spinocerebellar
- sympathetic
- sensory nucleus of trigeminal
Clues
CN
3 - ptosis, pupil dilated, eyeballs are out and down
4 - diplopia in while looking down
5 - I/l sensory loss (localised lesion on lateral side, not in pons)
6 - lateral gaze palsy
7 - I/l spasm of facial muscles
8 - hearing problem (nucleus of pons and medulla)
9, 10, 11 - difficulty in swallowing (nucleus ambiguous)
11 - hoarseness of voice
12 - I/L deviation of tongue.
- Pyramidal pathway - c/l hemiplegia
- spinothalamic - c/l
- spinocerebellar - I/l ataxia
- medial lemniscus - c/l
- medial longitudinal fasiclus - intranuclear opthalmoplegia
- sympathetic system - horner
- sensory nucleus - i/l for face.
Claude syndrome
3CN + red nucleus ( cerebellum is connected to opposite red nucleus via superior cerebellar penduncles)
- I/l 3rd nerve palsy and c/l ataxia
Benedikt syndrome
Weber syndrome + Claude syndrome + subthalamus
- i/l CN3, c/l hemiplegia, c/l ataxia, hemiballismus
C/l loss of proprioception/vibration
Dorsal mid brain syndrome
Parinaud syndrome
- due to tumor in penial gland
- no weakness and 3rd nerve involvement
- pretectal nucleus - upgaze palsy and argyl Robertson pupil
1) Lateral Medullary syndrome
2) medial medullary syndrome
1) Wallenberg’s syndrome
- spinothalamic - c/l sensory loss
- vestibular nucleus - nystagmus, vertigo,
- horner syndrome
- i/l facial sensation loss
- hoarseness, dysphagia
PICA stroke
2) C/l hemiplegia
- tongue deviation on same side
- c/l loss of vibration and steriognosis
Lateral pontine syndrome
Medial pontine
Vestibular - nystagmus, vertigo Spinothalamic Sympathetic Facial - I/l facial drop, loss of corneal reflex Chochlear - deafness
Corticospinal tract, CN6, 7
Syndrome and arteries
Medial pontine syndrome - pontine branch of basilar artery Lateral pontine syn - AICA Medial medullary - ant. Spinal artery Lateral medullary - vertebral > PICA Midbrain - Posterior cerebral artery
1) Millard Gubler
2) Raymond
3) Foville’s
1) affect on - Fascial nerve + Corticospinal + Abducent nerve
- I/l facial palsy + c/l hemiplegia + 6th CN palsy
2) 6th CN palsy + c/l hemiplegia ( Corticospinal Track)
3) horizontal gaze palsy ( horizontal gaze centre) + I/l facial nerve + c/l hemiplegia
