This document summarizes the anatomy and vascular supply of the pons and describes various clinical syndromes that can result from lesions in different regions of the pons. It discusses the tracts that pass through the pons, outlines the vascular territories supplied by different arteries, and describes symptoms associated with medial, lateral, ventral and dorsal pontine lesions. Specific syndromes described include Millard-Gubler syndrome, Raymond syndrome, ataxic hemiparesis, Foville syndrome, and Marie-Foix syndrome. Pontine hemorrhage presentations are also briefly outlined.

1. Pons anatomy
Dr Vaishal Shah
SR neurology
GMC Kota

2. The pons is part of the metencephalon (pons
and cerebellum)

3. Anterior
surface

4. Posterior surface

5. Tracts pssing
through pons
• The medial longitudinal fasciculus situated
dorsomedially. PPRF – ventral to MLF.
• The medial lemniscus, lies dorsal to the
corticospinal, corticobulbar, and corticopontine
fiber bundles.
• The ventral spinocerebellar, spinothalamic.
• Lateral tectospinal, rubrospinal,
corticopontocerebellar tracts.
• Auditory connections, including the lateral
lemniscus, the trapezoid body, and the superior
olivary nuclear complex.
• The brachium pontis or middle cerebellar peduncle
connects the ventral pons with the cerebellum.

8. Blood supply of pons

9. Vascular supply
• Paramedian vessels - supply the medial basal pons, including the pontine nuclei,
the corticospinal fibers, and the medial lemniscus.
• Short circumferential arteries - ventrolateral basis pontis.

10. Vascular supply
• Long circumferential arteries - most of the pontine tegmentum and part of the
middle cerebellar peduncles
1. Superior cerebellar artery - dorsolateral pons and brachium pontis, the dorsal
reticular formation, and the periaqueductal region.
2. Anterior inferior cerebellar artery – same area but in lower 2/3 pons
3. Internal auditory artery - supplies the auditory, vestibular, and facial cranial
nerves.

11. Symptoms in general
• Medial syndromes – Contralateral hemiparesis, ataxia
Ipsilateral INO, conjugate horizonatal gaze
palsy.
• Lateral syndromes – contralateral hemianaesthesia
Ipsilateral ataxia, hornor’s syndrome, sometimes
conjugate horizonatal gaze palsy
Bradley’s neurology in clinical practice

12. Ventral pontine syndromes
Millard-Gubler Syndrome – caudal ventromedial
pons - basis pontis and the fascicles of cranial
nerves VI and VII ( paramedian arteries )
1. Contralateral hemiplegia (sparing the face) is
due to pyramidal tract involvement.
2. Ipsilateral lateral rectus paresis (cranial nerve
VI) with diplopia.
3. Ipsilateral peripheral facial paresis (cranial
nerve VII).

13. Ventral pontine syndromes
Raymond Syndrome (alternating abducens
hemiplegia) – caudal ventromedial pons – ipsilateral
abducens nerve fascicles and the corticospinal tract
but spares cranial nerve VII (paramedian arteries)
1. Ipsilateral lateral rectus paresis (cranial nerve VI)
2. Contralateral hemiplegia, sparing the face, due to
pyramidal tract involvement

14. Ventral pontine syndromes
• Pure Motor Hemiparesis – caudal ventromedial pons – corticospinal tracts in the
basis pontis
1. pure motor hemiplegia with or without facial involvement. Patient often have
severe dysarthria and dysphagia.
• Bouts of uncontrollable laughter may also occur
• Other locations - posterior limb of the internal capsule, the cerebral peduncle,
and the medullary pyramid

15. Ventral pontine syndromes
• Dysarthria—Clumsy Hand Syndrome – basis pontis at junction of upper 1/3rd
and lower 2/3rd of pons
1. facial weakness and severe dysarthria and dysphagia occur along with
clumsiness, impaired finger dexterity, and paresis of the hand.
2. Hyperreflexia and a Babinski’s sign may occur on the same side as the arm
paresis, but sensation is spared.
• Other locations - lesions in the genu of the internal capsule or with small, deep
cerebellar hemorrhages

16. Ventral pontine syndromes
• Ataxic Hemiparesis - basis pontis at junction of upper 1/3rd and lower 2/3rd of
pons
1. Hemiparesis that is more severe in the lower extremity.
2. Hemiataxia on same side of paresis.
3. Occasionally dysarthria, nystagmus, and paresthesias.
• The ataxia is unilateral, probably because transverse fibers originating from the
contralateral pontine nuclei (and projecting to the contralateral cerebellum) are
spared

17. Ventral pontine syndromes
• Ataxic Hemiparesis
• Other locations
1. Contralateral thalamocapsular lesions
2. Lesions of the contralateral posterior limb of the internal capsule
3. Lesions of the contralateral red nucleus
4. With superficial anterior cerebral artery territory infarcts in the paracentral area

18. Ventral pontine syndromes
• Locked-in Syndrome – Bilateral ventral pons ( infarction, tumour,
haemorrhage, trauma, abscess, encephalitis, neuro-behcet’s, MS,
CPM, heroin abuse, diazepam toxicity )
1. Quadriplegia due to bilateral corticospinal tract involvement in the basis pontis.
2. Aphonia due to involvement of the corticobulbar fibers innervating the lower
cranial nerve nuclei
3. Occasional impairment of horizontal eye movements due to bilateral
involvement of the fascicles of cranial nerve VI

19. Ventral pontine syndromes
• Locked-in Syndrome – Bilateral
ventral pons
• Reticular formation is not injured, the patient
is fully awake.
• Vertical eye movements and blinking are
intact (the patient may actually convey his
wishes in morse code)

20. Dorsal pontine syndromes
Foville Syndrome - dorsal pontine tegmentum in
the caudal third of the pons
1. Contralateral hemiplegia (with facial sparing)
due to interruption of the corticospinal tract.
2. Ipsilateral peripheral-type facial palsy which is
due to involvement of the nucleus and fascicle
(or both) of cranial nerve VII.
3. Ipsilateral conjugate gaze palsy (gaze is “away
from” the lesion) due to involvement of the
PPRF or abducens nucleus, or both.

21. Dorsal pontine syndromes
• Raymond-Cestan Syndrome - dorsal pontine tegmentum in rostral pons
1. Ipsilateral Cerebellar signs (ataxia) with a coarse “rubral” tremor which is due
to the involvement of the cerebellum
2. Contralateral hypesthesia with reduction of all sensory modalities (face and
extremities) which is due to the involvement of the medial lemniscus and the
spinothalamic tract
3. Ipsilateral Paralysis of conjugate gaze toward the side of the lesion (due to
involvement of the PPRF).

22. LATERAL PONTINE SYNDROME
• Marie-Foix Syndrome - lateral pontine lesions affecting the brachium
pontis
• Ipsilateral cerebellar ataxia - cerebellar connections
• Contralateral hemiparesis - corticospinal tract
• Variable contralateral hemihypesthesia for pain and temperature -
spinothalamic tract

26. Rare presentations
• Anosognosia for the hemiplegia
• Blepharospasm
• Jaw-opening dystonia, hemidystonia ,
• Dysarthria-dysmetria or dysarthria-facial paresis
• Body lateropulsion from paramedian tegmental involvement ventral to the fourth
ventricle,
• Truncal ataxia without limb ataxia

27. Pontine haemorrhage
Massive variety
Classic picture of
• Coma
• Quardriplegia
• Horizontal ophthalmoplegia with/withut ocular bobbing
• Pinpoint reactive pupil
• Abnormal respiratory pattern - “inspiratory gasps of
apneustic respiration,” Cheyne–Stokes patterns, slow and
labored respirations, and gasping and apnea
• Hyperthermia

28. Pontine haemorrhage
• 4 types
1. Massive
2. basal-tegmental
3. bilateral tegmental
4. Small unilateral tegmental

29. Thank you