Anatomy of the Medulla

Question 1

Brain stem

Answer 1

part of CNS betwen diacephalon ( thalamus & hypothalamus ) and cranial end of spinal cord
It has 3 parts : Midbrain (from the lower part of the thalamus to the pons) / pons / medulla oblongata

Question 2

Functions of brain stem :

Answer 2

1- A conduit for ascending and descending tracts connecting spinal cord to cerebellum and different parts of the higher centers in the forebrain ( main structure that connects spinal cord to cerebellum, cerebrum, diacephalic structures )
2- controls reflex centers associated with control of resp and CVS system and control of consciousness ( reticular activating system )
3- contains nuclei of cranial nerve 3 and 12 ( except the olfactory and optic nerve all other cranial nerves originate from the brainstem region )

Question 3

Brain stem extends from?

Answer 3

The diancephalon ( thalamus and hypothalamus ) to the level of upper border of 1st cervical vertebra where its continuous with the spinal cord (So, lower part of medulla oblongata is passing through the foramen magnum and NOT SPINAL CORD) SC starts at a little lower level.

Question 4

What happens in increased intracranial pressure ?

Answer 4

The lower part of medulla oblongata and cerebrum herniate ( descendes down foramen magnum and gets injured at that
part )

Question 5

Cavities inside different parts of the brainstem :

Answer 5

Midbrain : cerebrum aqueduct

Pons, Medulla oblongata : 4th ventricle, continues down as the central canal of medulla oblongata

Question 6

Parts of medulla oblongata :

Answer 6

Lower closed part where the central canal of medulla oblongata is present

Upper open part where the 4th ventricle is present

Question 7

The central canal extends through the spinal cord and expands in the …… as …….

Answer 7

lumbar enlargement, terminal ventricle

Question 8

Cavity of cerebrum is called

Answer 8

Lateral ventricle ( right and left )

Question 9

Cavity between left and right thalamus is called

Answer 9

Third ventricle

Question 10

Rt and Lt ventricles communicates w 3rd ventricle through the ……

Answer 10

Interventricular foramen

Question 11

Ventricles are filled w …. produced by ….., which is……

Answer 11

CSF, choroid plexus : tough capillaries covered by ependyma

Question 12

Pathway of CSF

Answer 12

From lateral ventricles > IVF > 3rd ventricle > ceberal aqueduct (narrowest part of ventricular system) > 4th ventricle > general subarachnoid space ( median aperture & 2 lateral aperture ) > central canal of medulla > central canal of spinal cord
so the ventricle communicate w subarachnoid space at 3 points

Question 13

CSF goes down to ….

Answer 13

SC, cerebellum, all over the brain, then absorbed into the dural venous sinus via ARACHNOID VILLI (pressure difference)

Question 14

4th ventricle communicates with subarachnoid space through

Answer 14

foramen of Luska (related to medulla oblongata) and foramen Magendie

Question 15

What is cisterna ?

Answer 15

Largest (spacious) of the subarachnoid space

Question 16

Cerebellum is attached to the …….. on its …… . Cisterna magna or cerebellomedullary cistern is related to the …….. of the ……….

Answer 16

brain stem, dorsal side

dorsal side, medulla oblongata

Question 17

2.Middle cerebellar peduncle connects …… to …….. Interpeduncular fossa/cistern of subarachnoid space lie between the ……… of the………

Answer 17

pons, cerebellum

two crus cerebri, midbrain

Question 18

CSF flows through the ventricles and into the subarachnoid space via……….

Answer 18

median & lateral apertures

Question 19

Midbrain CN

Answer 19

CN III oculomotor, IV trochlear ( trochlear is the only cranial nerve arising from the dorsal aspect of the midbrain and it is crossed )

Question 20

Pons

Answer 20

CN V trigeminal

Question 21

Ponto-medullary junction

Answer 21

CN VI, VII. VIII (from med to lat - abducens, facial, vestibulotrochlear)

Question 22

Medulla

Answer 22

CN IX,X, XI, XII
( 9,10,11 attached to posterolateral sulcus,
12 attached to anterolateral sulcus )

Question 23

Anterior view of Medulla O :

1- Anterior median fissure :

Answer 23

continuation of the anterior median fissure of the spinal cord. Lower part of it is closed by decussation (crossing) of the pyramids

Question 24

2- pyramids :

Answer 24

Surface elevations produced by the underlying corticospinal (pyramidal) tract fibers.

Question 25

Olive

Answer 25

Oval shaped surface elevation produced by the underlying INFERIOR olivary nucleus in the grey matter inside the brain

Question 26

Between the pyramids and olive is the ……. rootlets of ……. are attached here

Answer 26

anterolateral sulcus, hypoglossal

Question 27

Posterior to …… is posterolateral sulcus. ……. CN are attached here

Answer 27

Olive, 9, 10, 11

Question 28

Sensory root of facial nerve is

Answer 28

between its motor root and vestibocochlear nerve ( CN VIII )

Question 29

Parts of accessory nerve CNXI

Answer 29

1- fibers attached to the posterolateral sulcus form the cranial root of spinal nerve
2- fibers coming from the upper five segments of the spinal cord form the spinal root of the cranial nerve

Question 30

Cranial nerve distributed through the

Answer 30

vagus nerve

Question 31

Spinal root supplies

Answer 31

2 muscles of the neck

Question 32

Ext surface of MO ( POST view )

Answer 32

1-Posterior median sulcus
2- Fasiculus gracilis terminating as Gracile tubercle produced by nucleus gracilis
3- LATERAL to it is fasculus cuneatus and cuneate tubercle
4- LATERAL MOST is ICP : connects MO and SC to cerebellum

Question 33

Cerebellum is connected to midbrain by 3 parts

Answer 33

SUP, MID, INF CP

Question 34

Upper part of the posterior surface medulla forms the lower part of the

Answer 34

Floor of 4th ventricle