medulla

Question 1

medulla provides attachment to which cranial nerves

Answer 1

glossopharyngeal
vagus
accessory
hypoglossal

Question 2

what does the upper part of the medulla form

Answer 2

the caudal part of the floor of the fourth ventricle

Question 3

what does the lower half of the medulla form

Answer 3

The lower half of the medulla is closed and contains the central canal which below
becomes continuous with the central canal of the spinal cord and above opens into
the fourth ventricle

Question 4

how is the medulla separated from the cerebellum

Answer 4

dorsally by the cavity of the fourth ventricle

Question 5

what is the medulla divided by

Answer 5

anterior median fissure

Question 6

what sulcus in the medulla gives attachment to hypoglossal nerve rootlets

Answer 6

Anterolateral sulcus

Question 7

what sulcus gives attachment to glossopharyngeal, vagus & cranial part of accessory nerve

Answer 7

Posterolateral sulcus

Question 8

in the anterior area of the M.O. what is the pyramid produced by

Answer 8

produced by the
underlying corticospinal,
corticobulbar and Corticopontine fibres

Question 9

what covers the ventral
surface of pyramid

Answer 9

Arcuate nuclei

Question 10

the Lateral area between the anterolateral
sulcus and posterolateral sulcus is continuous with what

Answer 10

lateral funiculus of the spinal cord

Question 11

what is the olive

Answer 11

is an elevation produced by
the underlying inferior olivary
nucleus

Question 11

what tracts are present in the lateral area

Answer 11

It is occupied by ventral spino-
cerebellar tract, dorsal spino-
cerebellar tract, lateral spino-
thalamic tract (spinal lemniscus), spino-olivary and olivo-spinal tracts

Question 12

where does the facial nerve emerge

Answer 12

between the olive and pons

Question 13

what forms the floor of
the fourth ventricle

Answer 13

Supero-medial zone of the posterior area

Question 14

what is the Tuberculum cinereum produced by

Answer 14

the underlying spinal
nucleus and spinal tract of trigeminal nerve

• The spinal nucleus of trigeminal below extends up to second c2 beyond which it becomes continuous with substantia gelatinosa of Rolando

Question 15

what is the function of the corticospinal tract

Answer 15

concerned with the
skilful, voluntary movements

Question 16

what area does the corticospinal tract originate from

Answer 16

Takes origin from areas 4,6,312

Question 17

what is the path of the corticospinal tract

Answer 17

Axons from these neurons
descend the corona radiata, posterior
limb of internal capsule,
middle two-third of crus
cerebri, basilar part of pons and
pyramid of medulla oblongata

In the lower medulla 90% of
fibres decussate and enter into
the lateral funiculus as the lateral
cortico-spinal tract

8% fibres pass uncrossed in the
anterior funiculus as the anterior
cortico-spinal tract

Question 18

how does the lateral corticospinal tract terminate

Answer 18

55% of fibres terminate in the cervical
segment of the spinal cord
20% of fibres terminate in the thoracic
segments of the cord
25% of fibres terminate in the lumbo-sacral
segments of the cord

Question 19

how does the anterior corticospinal tract terminate

Answer 19

THIS TRACT ONLY FOUND IN PRIMATES (MAN)
It extends up to mid-thoracic level
Depending on the level of termination all the
fibres of the tract cross the middle line in the
anterior white commissure and terminate in
the contra-lateral spinal grey matter

Question 20

The spinal tract of Trigeminal nerve conveys what

Answer 20

pain & thermalsensations from the ipsilateral trigeminal area of the face and forehead, and are relayed into the spinal nucleus of V nerve

Question 21

how is the trigeminal lemniscus formed

Answer 21

The axons of second sets of neurons arise from the spinal nucleus of the V nerve, cross to the opposite side, and form the trigeminal lemniscus

terminate in the VPM nucleus of thalamus

Question 22

how does the The spinal nucleus extend

Answer 22

caudally to the second cervical
segment and cranially to the pontomedullary junction

Question 23

The anterolateral funiculus on each side between the pyramid and spinal tract of
trigeminal contains the:

Answer 23

• Ventral and dorsal spinocerebellar tract
• Ventral and lateral spinothalamic tract
• Spino-tectal tract
• Spino-olivary tract
• Vestibulo-spinal tract
• Rubro-spinal tract

Question 24

what happens in medulla oblongata at the level of sensory decussation?

Answer 24

The nucleus gracilis and cuneatus become more pronounced and fibres of fasciculus
gracilis and fasciculus cuneatus terminate in these nuclei
The internal arcuate fibres arising from these nuclei decussate with the corresponding fibres of opposite sideand turn upwards as medial lemniscus on the opposite side
- Formation of medial lemniscus
- The medial lemniscus ends in the VPL nucleus
of thalamus

Question 25

what does the Accessory cuneate nucleus do

Answer 25

carries proprioceptive sensation from the upper limb to the cerebellum of the
same side through inferior cerebellar peduncle

Question 26

what does the Hypoglossal nucleus do

Answer 26

Occupies the hypoglossal triangle in
the floor of the 4th ventricle

• It supplies all the muscles of the
  tongue except the palatoglossus

Question 27

what does the Dorsal nucleus of vagus do

Answer 27

occupies the vagal
triangle in the floor of the 4th ventricle
 The preganglionic fibers arising
from this supply the heart, smooth
muscles and glands of respiratory
and alimentary system

Question 28

where does the Nucleus of tractus solitaries receive fibres from

Answer 28

It receives taste fibers from VII, IX
and X nerve

Question 29

what does the Nucleus of tractus solitaries do

Answer 29

Lies behind the dorsal nucleus of
vagus
Efferents from the solitary nucleus
carrying taste sensations ascend on
the contralateral side and terminate
in VPM of thalamus

Question 30

what does the Medial longitudinal bundle consist of

Answer 30

Is a small compact tract which interconnects different cranial nerve nuclei (3rd, 4th, 6th, 8th, and spinal nucleus of 11th)

Question 31

how is the medial leminiscus formed

Answer 31

The lateral and anterior spinothalamic tracts collectively form the spinal
lemniscus

Question 32

what does the Inferior olivary nuclear complex – beneath the olive consist of

Answer 32

 Principal inferior olivary nucleus
 Medial accessory olivary nucleus
 Dorsal accessory olivary nucleus

Question 33

what are the afferent Connections of olivary complex of nuclei:

Answer 33

Afferents – from cerebral cortex, red
nucleus, basal nuclei, thalamus,
periaqueductal grey of mid brain and
spinal cord

Question 34

what are the efferent Connections of olivary complex of nuclei:

Answer 34

Efferents:
Olivo-cerebellar tract from the
inferior olivary nu.
Parolivo-cerebellar fibres from
medial and dorsal accessory
olivary nu.
Both sets of fibers cross the median
plane and reach the cerebellum
through inferior cerebellar
peduncle
Parolivo-cerebellar fibers project to
the cerebellar vermis

Question 35

what do the Arcuate nuclei do

Answer 35

They are the displaced pontine nuclei, lie on the surface of the pyramid
b. Receive fibers from the cerebral cortex and send efferent fibers (anterior external arcuate
fibers) to the cerebellum of the opposite side

Question 36

what is the blood supply of the medulla

Answer 36

It is supplied by:
- Branches arising from the vertebral
arteries
 Anterior and posterior spinal
arteries
 Posterior inferior cerebellar
arteries
- Basilar artery and its branch
Anterior inferior cerebellar artery

Question 37

what is lateral medullary syndrome

Answer 37

Lesion/block in the branches of posterior
inferior cerebellar A supplying the medulla
oblongata

Question 38

what are the symptoms of lateral medullary syndrome

Answer 38

Vertigo – sensation of whirling and loss of balance
Nystagmus – rapid involuntary movements of the eye
Ataxia – loss of full control of bodily movements
Dysmetria – lack of coordination of movement
Dysdiadokokinesis – inability to perform rapid alternate movements
Palatal myoclonus – rapid spasm of palatal muscles
Dysphagia – difficulty in swallowing
* Gag reflex or pharyngeal reflex
Miosis – excessive constriction of pupil
Anhydrosis – failure of sweat glands to secrete

Question 39

what is medial medullary syndrome

Answer 39

(Dejerine syndrome)
Lesion/block in the vertebral
artery branches supplying the
medulla oblongata