The pons is the bridge-shaped structure that connects the midbrain to the medulla oblongata. It contains fibers that connect the cerebellum and midbrain. The pons has a ventral surface with sulcus basilaris and lateral continuations with the middle cerebellar peduncle. It attaches to the 6th, 7th and 8th cranial nerves ventrally. Dorsally, it forms the upper part of the floor of the 4th ventricle. Internally, it contains longitudinal and transverse fibers, pontine nuclei in the basilar part, and ascending and descending tracts in the tegmental part such as the medial lemniscus and trigeminal lemn

1. ANATOMY OF PONS
AND CEREBELLUM
DR PRATIK MISTRY

2. PONS

3. INTRODUCTION
• Pons means “bridge”
connect midbrain and
hind brain
• Extent
• Relations: ventrally and
dorsally
• Laterally connected
with middle cerebellar
peduncle

4. EXTERNAL FEATURES
• VENTRAL SURFACE:
 Sulcus basilaris
 Laterally continue with
MCP
 Show transverse ridges
and grooves because of
ponto-cerebellar fibres
 Ponto-medullary junction
attachment to 6th, 7th, 8th
CN
 Cerebello-pontine angles

5. EXTERNAL FEATURES
• DORSAL SURFACE:
 Form upper part of floor of
4th ventricle above
medullary stria
 Facial colliculus formed by
 Vestibular area
 Locus ceruleus (substantia
ferruginea)

6. INTERNAL FEATURES
• Ventral, basilar part (pons proper)
• Dorsal, tegmental part

7. BASILAR PART
• Traversed by longitudinal &
transverse fibres and
scattered pontine nuclei
• Longitudinal fibres
• Transverse fibres
• Nuclei pontis and their role

8. TEGMENTAL PART
• Traversed by number of ascending and descending
tracts
• Contain decussation of trapezoid body, nuclei of 6th, 7th,
8th and 5th cranial nerves
• Also has pontine reticular formation
• Described in two parts:
1. At the level of facial colliculus
2. Above the level of facial colliculus

9. AT THE LEVEL OF FACIAL
COLLICULUS
• Necklace of
ascending tracts
• Medial lemniscus
• Trigeminal
lemniscus
• Spinal lemniscus
• Trapezoid body
• Nucleus of
trapezoid body and
superior olivary
nuclear complex

10. AT THE LEVEL OF FACIAL
COLLICULUS
• Dorsally, motor
nucleus facial nerve
• Abducent nucleus
• neurobiotaxis
• Superior salivatory
nucleus
• Nucleus of spinal
tract of 5th CN
• Central tegmental
tract

11. AT THE LEVEL OF FACIAL
COLLICULUS
• In the middle,
• MLF
• Tecto-spinal tract
• Rubro-spinal tract

12. AT THE LEVEL OF FACIAL
COLLICULUS
• Dorso-laterally
• Middle cerebellar
peduncle
• Ventral & dorsal
cochlear nuclei
• Ant. Spino-
cerebellar tract
• Part of inferior
cerebellar peduncle
• Vestibular nuclei

13. SECTION OF PONS ABOVE
THE FACIAL COLLICULUS

14. ABOVE THE LEVEL OF FACIAL
COLLICULUS
• Smaller cavity of 4th
ventricle bounded
by
• Ant. Spino-
cerebellar tract
• Middle cerebellar
peduncle with
motor and sensory
roots of 5th nerve

15. ABOVE THE LEVEL OF FACIAL
COLLICULUS
• Motor nucleus of
5th nerve
• Principal sensory
nucleus of 5th nerve
– touch & pressure
• Mesencephlic
nucleus of
trigeminal nerve –
proproiceptive
fibres from muscles
of mastication &
TM Joint

16. APPLIED ANATOMY
• Cerebello-pontine
syndrome (acoustic
neuroma)
• Raymond’s syndrome
(alternate abducent
hemiplegia)
• Millard- Gubler syndrome
(alternate facial
hemiplegia)
• Foville syndrome
• Alternating trigeminal
hemiplegia
• Pontine haemorrhage