BRAINSTEM

BRAINSTEM

BRAIN STEM

3 PARTS : MIDBRAINPONS MEDULLA OBLANGATA

HAS 3 BROAD FUNCTIONS Serves as a conduit for the ascending & descending tracts Contains important reflex centers(RS.CVS) Control of consciousness Contains cranial nerves nuclei (CN3-CN12)

Brainstem occupies the posterior cranial fossa of the skull

MIDBRAIN

MIDBRAIN VENTRAL SURFACECrus cerebri of midbrainOptic tractMammillary bodyPosterior perforated substanceOculomotor nerveTrochlear nerveInterpedencular fossa

MIDBRAIN (Dorsal surface)

BLOOD SUPPLY OF MIDBRAINARTERIAL SUPPLY:Posterior cerebral artery.Superior cerebellar artery.VENOUS PLEXUS:Basal vein.Great cerebral vein.

PONS

PONS(Ventral view)Basilar grooveMotor root of trigeminal nerveSensory root of trigeminal nerveAbducent nerveRoots of facial nerve vestibulocochlear nerve

PONS (dorsal view)Trochlear nerveSuperior medullary velumFloor of 4th ventricleStriae medullarisMedian sulcusMedial eminenceFacial colliculusSulcus limitansVestibular areaHypoglossal triangleVagal traingle

BLOOD SUPPLY OF PONSARTERIAL SUPPLY:Pontine branches of basilar artery.Superior cerebellar artery.Anterior inferior cerebellar artery.VENOUS SUPPLY:Basilar venous plexus.Inferior petrosal sinuses.

MEDULLA OBLANGATA

THE ANTERIOR SURFACE (medulla)

On the anterior surface of the medulla is the anterior median fissure (Continuous with the AMF of the spinal cord)

PYRAMIDS

( decussation of the pyramids) in lower portion.

OLIVES (Inferior olivary nuclei lies beneath them) INFERIOR CEREBELLAR PEDUNCLEHYPOGLOSSAL NERVE (XII) ( groove between the pyramids & olives )

THE ANTERIOR SURFACE (medulla)From the grove between the olives & the inferior cerebellar peduncle, emerge the nerve roots of: Glossopharyngeal (IX) Vagus (X) Accessory nerve (XI) Cranial roots

THE POSTERIOR SURFACE (medulla)

Superior half : FLOOR OF THE 4TH VENTRICLEInferior half : POSTERIOR MEDIAN SULCUS (PMS) GRACILE TUBERCLE (Produced by underlying gracile nucleus) CUNEATE TUBERCLE (Produced by underlying cuneate nucleus)

BLOOD SUPPLY OF MEDULLAARTERIAL SUPPLY:Medullary br. of vertebral artery.Medullary br. Of basilar artery.Posterior inferior cerebellar artery.Anterior spinal artery.VENOUS SUPPLY:Basilar venous plexus.Inferior petrosal sinus.Occipital sinus.

FUNCTION OF THE BRAINSTEMMidbrain:Visual & auditory processing and reflexesFine-tuning of voluntary movements

Pons:Relay station for cerebellumControl of sub-conscious movement

Medulla Oblongata:Control of cardiovascular functionsControl of respirationControl of gastrointestinal functions

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What brainstem structures are visible here?MID BRAINPONSMEDULLA

Cranial Nerves

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