Pons

Question 1

External features of ventral surface of pons

Answer 1

• convex
• transversely striated due to ponto cerebellar fibres
• Basilar groove
• Pontine cistern
• Motor and sensory roots of trigeminal N

Question 2

External features of dorsal surface of pons

Answer 2

• covered by cerebellum
• separated from it by 4th ventricle
• superior border made of cerebellar peduncles with superior cerebellar A
• inferior border continuous with medulla. Has anterior inferior cerebellar A

Question 3

Internal structure of basilar part of pons

Answer 3

1. Corticopontine f. relay in ipsi. pontine nuclei
2. Corticonuclear f. end in contra. motor nuclei of cranial N
3. Corticospinal f. form pyramids
4. Pontocerebellar f. cross to opp. middle cerebellar peduncle
5. Pontine nuclei - cortico ponto cerebellar pathway

Question 4

Internal structure of tegmental part of pons

Answer 4

TRAPEZOID BODY

- Nucleus of 5, 6, 7, 8 nerves

Question 5

Grey matter of caudal part of pons

Answer 5

1. Abducens N nucleus beneath facial colliculus
2. Facial N nucleus lateral to abducent
3. Superior, inferior salivatory and lacrimatory nucleus
4. Nucleus of tractus solitarius
5. Vestibular ucleus
6. Cochlear nucleus
7. Spinal nucleus of trigeminal nerve

Question 6

White matter of caudal part of pons

Answer 6

1. Trapezoid body formed by decussation of cochlear fibres
2. Medial lemniscus
3. Spinal lemniscus
4. Medial longitudinal bundle
5. Tectospinal tracts
6. Spinal tract of trigeminal nerve

Question 7

Grey matter of cranial part of pons

Answer 7

1. Motor and sensory nuclei of trigeminal N

Question 8

White matter of cranial part of pons

Answer 8

1. Ascending tracts as seen in caudal part
2. Lateral lemniscus
3. Trigeminal lemniscus made of trigeminothalamic fibres

Question 9

Blood supply of pons

Answer 9

Pontine branches of basilar A

Anterior inferior cerebellar A

Question 10

Millard - Gubler syndrome

Answer 10

Lesion in lower part of pons

1. Ipsi. medial squint as abducent N is affected
2. Ipsi. facial palsy as facial N
3. Contra. hemiplegia as corticospinal tract

Question 11

Pontocerebellar angle syndrome

Answer 11

Due to pressure exerted on lateral region of caudal part of pons by acoustic neuroma - a tumor developing from Schwann cells around cochlear N

1. Tinnitus
2. Vertigo
3. Ipsi. ataxia
4. Staggering gait
5. Ipsi. LMN facial palsy
6. Ipsi. loss of pain and temp.
7. Ipsi. loss of corneal reflex

Question 12

Pontine haemorrhage

Answer 12

1. Pin point pupil
2. Hyperpyrexia
3. Deep coma
4. Bilateral paralysis of face and limbs