BRAINSTEM: PONS

Pons is __ to cerebellum

anterior

Pons means

bridge

The pons is __ from side to side

convex

What kind of fibers converge on each side and what do they form

transverse fibers

middle cerebellar peduncle

Groove in midline of pons

Basilar groove

T or F: Basilar groove is shallow

True

What is in the basilar groove

basilar artery

What is found on the anteriolateral surface of the pons

Trigeminal nerve

Parts of the trigeminal nerve

Motor root

Sensory root

Motor root of trigeminal nerve

Smaller and medial

Sensory root of trigeminal nerve

Larger and lateral

What is found in the groove bw pons and medulla (arrange from medial to lateral)

AFV - CN 6, 7, 8

Abducens

Facial

Vestibulocochlear ns

What does the posterior pons form

upper half of 4th ventricle

The posterior pons is limited laterally by

superior cerebellar peduncle

What divides the pons into halves

median sulcus

Lateral to the median sulcus

medial eminence

the medial eminence is bounded laterally by

sulcus limitans

The inferior end of the medial eminence forms

the facial colliculus

What makes the facial colliculus

root of facial n → wraps around nucleus of abducens n

What do you call the floor of the superior part of the sulcus limitans

substantia ferruginea

color of substantia ferruginea

bluish-gray

Lateral to sulcus limitans

area vestibuli

What is the pons divided into & what are they divided by

Pos part

Tegmentum

Anterior basal part

Div by: Trapezoid body

Levels of the pons

1. Caudal part - through facial colliculus

2. Cranial part - through trigeminal nuclei

The __ rotates as it passes from the medulla to the pons

medial lemniscus

Where is the medial lemniscus located

most anterior part of tegmentum

Long axis of the medial lemniscus is __ (orientation)

transverse

The medial lemniscus is accompanied by

spinal and lateral lemnisci

Posterior to the lateral part of medial lemniscus

facial nucleus

Fibers of the facial n path

ant bw facial nucleus & nucleus of spinal tract of trigeminal n

Loc of MLF

under 4th ventricle

MLF is the main pathway for

vesitbulocochlear nuclei to nuclei of extra-ocular muscles

Nuclei in MLF

4 Cranial nuclei

3,4,6,8

T or F: The MLF is heavily myelinated

True

T or F: In MS, the facial nucleus is affected

FALSE

Facial nerve is affected not nucleus

Medial vestibular nucleus is lateral to what nucleus

abducens nucleus

Which cerebellar peduncle is in close relationship to the medial vestibular nucleus

Inferior cerebellar peduncle

Which vestibulocochlear nuclei are found at the lvl of the caudal part

Lateral vestibular nucleus (superior part)

Superior vestibular nucleus (inferior part)

Ant & pos cochlear nuclei

This lies anteromedially to the inferior cerebellar peduncle

nucleus and tract of the spinal tract of the trigeminal nerve

Trapezoid body is made up of fibers from

Cochlear nuclei

nucleus of trapezoid body

T or F: The trapezoid body runs transverse at the posterior part of the tegmentum

False

anterior part

Part of pons that contains small masses of n cells called pontine nuclei

basilar part

Basilar part: Where do the corticopontine fibers of the crus cerebri terminate

with pontine nuclei

What do the axons of the pontine nuclei give rise to

transverse fibers of pons

Path of transverse fibers of the pons

cross midline → intersect corticospinal and corticonuclear tracts → creates small bundles

What is the connection that forms the main pathway linking the cerebral cortex to the cerebellum

transverse fibers of pons → enters middle cerebellar peduncle → distributed to cerebellar hemisphere

Transverse section through the cranial part contains

motor and sensory nuclei of trigeminal n

Location of the motor nucleus of trigeminal nerve

under lateral 4th ventricle in reticular formation

Path of fibers of motor nucleus of trigeminal nerve

fibers go anterior → substance of pons → exit ant pons

What is the pathway of principal sensory nucleus of trigeminal nerve

continues inferiorly with nucleus of spinal tract → enters the substance of pons → lateral to the motor fibers

Characteristics of principal sensory nuclei and motor nuclei

principal sensory: lateral, larger

motor: medial, smaller

Sup cerebellar peduncle in relation to motor nucleus

posterolat to motor nucleus of trigeminal nerve

What tract joins the sup cerebellar peduncle

anterior spiniocerebellar tract

Difference in terms of the location of trapezoid body and medial lemniscus in the cranial part as compared to the caudal part

none

Where is the lateral and spinal lemniscus loc

lateral extremity of medial lemniscus