Neuro: Division of BS Flashcards
What are the 3 longitudinal divisions of the brainstem?
Basilar - front
Tegmentum - middle
Tectum - back
The tectum is only found in the….
Midbrain
What does the tectum consist of?
Superior + inferior colliculus and pretectum
What is inside of the tegmentum
Reticular Formation
Sensory nuclei and ascending sensory tracts
CN V nuclei
Medial longitudinal fasciculus (coordinates head and eye mvmt)
Really Some Cool Moves
What is inside of the basilar division?
descending axons from cerebral cortex, corticospinal, corticobrainstem, corticopontine, and corticoreticular tracts
Motor nuclei from substantia nigra, pons, and inferior olive
Basically a bunch of motor stuff (all tracts that start with cortico-)
pontocerebellar axons
What is in the basis pedunculi?
Cerebral peduncles
substantia niagra nucleus
What does the superior colliculus do?
motor and sensory info to orient head and eyes
What does the inferior colliculus do?
relays info from cochlear nerve to superior colliculus and thalamus
The pretectal area of the midbrain does what?
mediates eye reflexes
What kind of matter is the red nucleus made out of?
Gray matter (part of cognitive and motor circuit)
What cranial nerve nuclei are found in the midbrain tegmentum
3 and 4
What 2 tracts synapse in the pons? Most of the tracts do not
corticopontine tract- Synapse on pontine nuclei -> pontocerebellar fibers -> middle cerebellar peduncle -> synapse in contralateral cerebellar hemisphere
corticobrainstem tract - synapses with trigeminal motor nucleus and facial nucleus
What kind of fibers are in the superior cerebellar peduncle?
Sensory fibers
What can you find in the basilar portion of the pons?
Descending tracts- corticospinal, corticobrainstem, corticopontine
Pontine nuclei
Pontocerebellar axons
What can be found in the tegmentum of the Pons?
Sensory Tracts
Reticular Formation
Autonomic pathways
CN 5,6,7,8 nuclei
What cranial nerve nuclei exits between the pyramid and inferior olive?
CN 12
What is the nucleus ambiguus for?
Motor output to swallowing/vocalization muscles
(Which would be CN 9, 10, 12)
What is the only tract that enters the medulla from the cerebellum
(The rest enter medulla -> inferior cerebellar peduncle -> cerebellum)
Cerebellovestibular tract
The DCML crosses in the inferior medulla ________ to the crossing of the corticospinal tract
Posterior
The anterior inferior cerebellar artery supplies the _____ whereas the Posterior inferior cerebellar artery supplies the _______
Pons
Medulla
What are the 4 brain stem tracts?
Rubrospinal Vestibulospinal Reticulospinal Tectospinal
What are the general brain stem functions
Modulates conciousness
Regulates vital signs
Conveys signal from cortex to spinal cord
What are the 4 cardinal signs of brain stem dysfunction? 4 Ds
Dysphagia, Dysarthria, diplopia, dysmetria
Damage to brain stem could cause….
Heart to stop beating
BP to fluctuate
Breathing to stop
Disorders of conciousness are due to damage of_______
Reticular activating formation/ reticular formation
People in vegetative or minimally concious states have loss of tissue in subcoritcal/thalamic/brainstem regions
Anteriormedial midbrain syndrome (webers) is caused by….
Blockage of PCA or Basilar artery
What are the primary structures affected by Anteromedial midbrain syndrome (webers)
Corticospinal tract- contralateral motor paralysis
Occulomotor nerve nucleus- Ipsilateral loss of eye movements. Paralysis of eyelid, dilated pupil
Red Nucleus- loss of motor coordination, ataxia, CONTRALATERAL, inappropriate laughing and crying. Lability
What does CN3 palsy look like?
Eye deviated down and out
Lateral inferior pontine syndrome is due to occlusion of the….
Anterior inferior cerebellar artery
What are the clinical manifestations of lateral inferior pontine syndrome
What artery?
Cochlear nucleus- ipsilateral hearing loss
Vestibular nucleus affected- dysequilibrium, nausea, vomiting
Impaired descending sympathetic- ipsilateral Horner’s syndrome
Trigeminal nerve- ipsilateral pain and temp loss of face
Salivatory nucleus- decreased tears and salivation
Spinothalamic tract- contralateral pain and temperature sensation to body
Facial nerve- ipsilateral loss of facial muscles
Remember, Trigeminal, Facial, And Vestibulocochlear nerve are all on the pons and the pons is supplied blood by AICA
Damage to what nerve causes Bell’s palsy
How will Bell’s palsy differ from a facial weakness after stroke
Facial nerve
Stroke is usually only lower facial weakness
(Upperface muscle preserved due to dual innervation of the upper face)
What is Horner’s syndrome?
Miosis- pupil constricted
Ptosis- drooping eye lid
Anhidrosis- drying of skin in the area
Damage to sympathetic nerves
Locked in syndrome is due to damage of the….
Basiliar artery impacting the ventral pons bilaterally
What are the primary structures involved in locked in syndrome-
B corticospinal tracts- paralysis below the head
B corticobulbar tracts- paralysis of facial muscles
B abducens tracts- unable to move eyes to side
Note: most of the time cranial nerve 3 is preserved but sometimes its impacted
What are spared in locked-in syndrome?
Reticular activating formation/ reticular formation
Vertical gaze centers are spared.
Middle medullary syndrome is caused by a blockage in the ….
Anterior spinal artery
What is the 2nd most common place to have a stroke in the brainstem?
AICA
What are the primary structures affected by medial medullary syndrome
hypoglossal nerve- ipsilateral tongue protrusion
DCML- contralateral loss of DCML senses
Lateral corticospinal- contralateral hemiparesis
Remember the hypoglossal nerve comes off of the medial medulla!
What is the most common brainstem stroke, and what artery causes it?
Lateral medullary syndrome (wallenberg)
Due to blockage of PICA
What structures are affected due to Wallenberg syndrome (lateral medullary syndrome)
Vagus nerve/Solitary nucleus- elevated HR
Vestibular nucleus- balance
Vagus nerve nucleus- altered vitals
Trigeminal Nerve
Inferior cerebellar peduncle - ataxia/coordination ipsilateral
Salivatory nucleus - unable to salivate or make tears
Spinothalamic tract- contralateral
Descending sympathetic- ipsilateral Horner syndrome
Nucleus ambiguus (9 10) and 12 cranial nerve. Tongue/ larynx/pharynx affected. Lack of gag reflex
The reticular formation is in the _______ of the pons
tegmentum
