Brain stem - General anatomy, location, anterior and posterior views... Blood vessels in contact with it... A brief review of the various brain stem structures like we got MOTOR PATHWAY (CORTICOSPINAL TRACT), MEDIAL LEMINISCUS, MEDIAL LONGITUDINAL FASCICULUS, SPINOCEREBELLAR TRACT, SPINOTHALAMIC TRACT..... and there effect of lesion. We also got here the applied, clinical part discussion in brief related to it.... BRAIN STEM LESIONS, of course...like lateral and medial medullary syndrome, RAYMOND-FOVILLE SYNDROME, MILLARD-GUBLER SYNDROME, CEREBELLO-PONTINE SYNDROME, WEBER’S SYNDROME, ALTERNATING TRIGEMINAL HEMIPLEGIA, BENEDICT’S SYNDROME, PARINAUD’S SYNDROME.... to name a few... We also discussed about BRAIN DEATH a little. THANK YOU

1. BRAIN STEM LESIONS

2. *BIKRANT ROY

3. GENERAL
ANATOMY

4. It is situated in the posterior
cranial fossa, and its ventral
surface lies on the clivus.
CEREBELLUM
CEREBRUM
BRAIN STEM

5. The Brainstem
consists of the
medulla oblongata,
pons and midbrain.
MIDBRAIN
PONS
MEDULLA

10. REVIEW OF
THE
BRAIN STEM
STRUCTURES

11. EFFECT OF
LESION-
Contralateral
weakness
MOTOR PATHWAY
(CORTICOSPINAL
TRACT)
CEREBRAL CORTEX
BRAIN
STEM
Arise from
voluntary
motor area
of cortex
10% 90%
LMN TO
SKELETAL
MUSCLES

12. EFFECT OF
LESION-
Contralateral
proprioception
loss
MEDIAL
LEMINISCUS
MEDIAL
LEMINISCUS
SENSORY
DECUSSATION
NUCLEI
CUNEATUS AND
GRACILIS
POSTERIOR
NERVE
ROOTS
FASCICULUS
CUNEAIUS AND
GRACILIS

13. EFFECT OF LESION-
Ipsilateral
internuclear
ophthalmoplegia
MEDIAL
LONGITUDINAL
FASCICULUS

14. When an attempt is
made to gaze contra
laterally (relative to the
affected eye), the
affected eye adducts
minimally, if at all. The
contralateral
eye abducts, however
with nystagmus.

15. EFFECT OF
LESION-
Ipsilateral
ataxia
SPINOCEREBELLAR
TRACT CEREBELLUM
2ND order neuron in
spinocerebellar tract
Fibres do not cross or if it
does it comes back
Axons of First
order neuron
Muscle Spindle
Proprioceptors

16. EFFECT OF LESION-
Contralateral
pain, temperature
sensory loss
SPINOTHALAMIC
TRACT
CEREBRAL CORTEX
To perspective
areas
3RD order
neuron to
cerebral
cortex
1ST order
sensory
neuron
Pain and Temperature
BRAINSTEM
Axons of 2ND order
neuron in
Spinothalamic tract
LESION

17. APPLIED

18. MEDIAL MEDULLARY
SYNDROME
ALTERNATING HYPOGLOSSAL HEMIPLEGIA
Occlusion of the anterior spinal artery and it’s
paramedian branches.
Lesion effects-
1. Hypoglossal nerve – Ipsilateral lower motor neuron
paralysis of tongue
2. Corticospinal tract and Medial leminiscus –
Contralateral upper motor neuron paralysis and loss of
discriminative senses of the body

19. The tongue muscles of
the affected side
undergo atrophy, and
when protruded, the tip
of the tongue is deviated
to the unaffected side
due to the unopposed
action of contralateral
GENIOGLOSSUS muscle.

20. LATERAL MEDULLARY
SYNDROMEWALLENBURG’S SYNDROME
Occlusion of posterior inferior cerebellar artery
damaging postero lateral part of the medulla.
Lesion effects –
1. Lateral spinothalamic tract – Contralateral loss of pain
and temperature from the body
2. Trigeminal nerve and spinal nucleus – Ipsilateral loss of
pain and temperature from the body
3. Nucleus Ambiguus – Ipsilateral paralysis of the muscles
of soft palate, pharynx and larynx

21. 4. Inferior Vestibular nucleus – Vertigo/ diplopia/
nystagmus/ vomiting
5. Sympathetic fibres – Ipsilateral Horner’s
syndrome
6. Central Trigeminal tract – Palatal clonus
7. Inferior Cerebellar peduncle - Ataxia

22. RAYMOND-FOVILLE
SYNDROME
ALTERNATING ABDUCENT HEMIPLEGIA
Lesion in the medial part of caudal pons
Ipsilateral paralysis of lateral rectus
producing internal strabismus and
contralateral hemiplegia

23. MILLARD-GUBLER
SYNDROME
ALTERNATING FACIAL HEMIPLEGIA
Lesion in the ventral part of caudal pons involving the
basis pontis and the fascicles of cranial nerves VI and VII
Lesion effects –
1. Pyramidal tract – Contralateral hemiplegia
2. Abducent nerve – Ipsilateral lateral rectus palsy with
diplopia
3. Facial nerve – Ipsilateral facial palsy

24. CEREBELLO-PONTINE
SYNDROME
At cerebello-pontine angle
Lesion effects –
1. Vestibulocochlear nerve – Persistent tinnitus,
progressive deafness on the affected side, nystagmus,
nausea, vomiting and vertigo
2. Ipsilateral coarse intention tremor, dysmetria,
adiadochokinesis and ataxia
3. Wallenberg's Syndrome
4. Facial nerve – Ipsilateral LMN paralysis of the muscles
of face, loss of taste from anterior two-third of tongue

25. WEBER’S SYNDROME
 At the level of Mid-brain
 Lesion effects –
1. Oculomotor nerve – Ipsilateral
LMN paralysis of the eye muscles
supplied by it. Pupillary
dilatation, if the EDINGER-
WESTPHAL NUCLEUS is also
involved
2. Basis Pedunculi of the mid brain
along with corticospinal tracts –
Contralateral hemiplegia of the body

26. ALTERNATING TRIGEMINAL
HEMIPLEGIA
Lesion in the lateral part of
the mid pons
Ipsilateral absence of all
general senses of the face
and the forehead, and LMN
paralysis of the Muscles of
Mastication and
contralateral hemiplegia

27. BENEDIKT’S SYNDROME
 Lesion of mid brain tegmentum
 Lesion effects –
1. Ipsilateral oculomotor palsy
2. Medial Leminiscus –
Contralateral pain, touch,
temperature, vibratory and
proprioceptive sensations lost
3. Red nucleus and Superior
cerebellar peduncles – Tremor,
chorea and athetosis

28. PARINAUD’S SYNDROME
 DORSAL MIDBRAIN SYNDROME
Lesion affecting the
tectum of mid brain in the
region of superior colliculi
 In children, aqueductal stenosis
and pinealoma
 In adults, demyelination,
trauma and A-V malformations
 In elderly, vascular accidents
and posterior fossa aneurysms

29.  Supranuclear up gaze
palsy
 Large pupils with light-
near dissociation
 Lid retraction (Coller’s
sign)
Normal down gaze
Convergence
weakness
Convergence-
retraction nystagmus

30.  Persistent loss of consciousness or coma indicates disorder of
the arousal mechanism in the brainstem and diencephalon.
 Diagnosis in a comatose patient is made on the basis of
absence of function of the brainstem, e.g., failure of
spontaneous respiration, absence of reflexes mediated by any
of the cranial nerves, etc.
 The widespread availability of mechanical ventilators has
resulted in the survival of patients with severe and
irreversible brain damage, who otherwise would have died.

31. THANK YOU!!!