Brainstem Flashcards
(10 cards)
BRAINSTEM: Midbrain
inclined + enters
cerebral aqueduct - lined by, surrounded by
colliculi other name
clinical - midbrain trauma = CN3 muscle (2), endinger sx (2), CN4 muscle (1)
- inclined ant, enters opening in tentorium cerebelli
- cerebral aqueduct: lined by ependymal cells, surrounded by gray matter
- colliculi/corpora quadrigemina
midbrain trauma
- CN3 = ipsilateral levator palpebrae, obliques
- CN4 = contralateral sup oblique
- edinger-westphal = bye light constriction & accommodation
BRAINSTEM: Midbrain
pos surface
- CN: below, enter, decussate
ant surface
- interpeduncular fossa: bounded
- CN: groove, pass where
internal structures
- cerebral peduncle: divided into (2) by what
- tectum: where to aqueduct, has
- mesencephalic nucleus of CN5: for
- decussation of SCP: where (2)
- reticular formation: vs. pons RF, where to SCP, where
- crus cerebri: contains, fronto/temporopontine fibers (med/lat)
ANTERIOR SURFACE
- interpeduncular fossa: bounded by crus cerebri
- CN3: groove on crus cerebri, passes cavernous sinus
POSTERIOR SURFACE
- CN4: below inf colliculi, enters wall of cavernous sinus, decussate at superior medullary velum
INTERNAL STRUCTURES
- cerebral peduncle: divided by substantia nigra into crus cerebri (ant) & tegmentum (pos)
- tectum: pos to aqueduct, has 4 colliculi
- mesencephalic nucleus of CN5: proprioception of head & neck
- decussation of SCP: ant to aqueduct, center of tegmentum
- reticular formation: smaller than pons RF, lat to SCP in tegmentum
- crus cerebri: contains descending tracts; frontopontine fibers (med) & temporopontine fibers (lat)
BRAINSTEM: Midbrain
- inf colliculus: receive, purpose, brachium, go to
- sup colliculus: purpose, brachium, go to, afferent (3) efferent (2), pretectal nucleus
- substantia nigra: between, polar + produce, for, connected to (4)
- red nucleus: between, efferent (4)
substantia nigra
- between crus cerebri & tegmentum
- has multipolar, produce dopamine
- for muscle tone
- connected to: spine, cortex, hypothalamus, basal nuclei
red nucleus
- between substantia nigra & aqueduct
- efferent: thalamus, substantia nigra, rubrospinal tract, rubroreticular tract
COLLICULI/CORPORA QUADRIGEMINA
inf colliculus
- receive from lat meniscus
- for auditory
- pass inferior brachium, go to medial geniculate body (thalamus)
sup colliculus
- for visual
- pass superior brachium, go to lateral geniculate body (thalamus) & optic tract
- afferent: CN2, visual cortex, spinotectal tract
- efferent: tectospinal & tectobulbar tract
- pretectal nucleus: where light reflex pathway ends
BRAINSTEM:
laminar, fontanelle (purpose), shape, connect, artery (2)
- unilaminar, stalk
- connect spine to forebrain
- vertebral & basilar artery
- fontanelle: state hydration
BRAINSTEM: Medulla
junction with spine - level, origin of
shape, directed, cont (up & down)
levels
pyramid decussation - other name, tract in sup vs. inf medulla, substantia gelatinosa (cont with what nucleus)
medial lemniscus - other name, where to pyramids, fiber
olives - has increased what, largest olivary nucleus & purpose, inf olivary nucleus (enter/end), vestibulocochlear (for), ambiguus (CN + deep within + for), CGM (deep within + 4)
- junction with spine: foramen magnum, origin of CN1 roots
- conical, directed upwards
- cont superiorly with central canal, inferiorly with 4th ventricle
level of pyramid decussation
- great motor decussation
- sup medulla has corticospinal, inf medulla has LWC
- substantia gelatinosa: cont with nucleus of spinal tract of CN5
level of lemnisci decussation
- great sensory decussation: above & pos pyramids
- has internal arcuate fibers
level of olives
- has inc gray matter
- olivary nucleus: for voluntary muscle
- inf olivary nucleus: largest; enter ICP into cerebellum
- vestibulocochlear: sup med lat inf vestibular, ant pos cochlear
- nucleus ambiguus (CN9-11): deep within RF, for voluntary skeletal
- central gray matter: deep within RF; nucleus ambiguus, nucleus of solitary tract, CN10 & CN12
BRAINSTEM: Medulla
anterior surface
- ant median fissure: cont, swelling
- pyramids: what, site of
- ant external arcuate fibers: emerge, enter
- olives: what/from, where to pyramids
- CN12: between
- CN9-11: between
- ICP: connect, where to olives
posterior surface
- pos median sulcus
- gracile tubercle: describe, from
- cuneate tubercle: where to GT
- ventricle
ANTERIOR SURFACE
- ant median fissure: cont with spine fissures; swelling on side = pyramids
- pyramid: corticospinal fibers; site of decussation
- anterior external arcuate fibers: emerge from ant median fissure, enter ICP
- olives: from inf olivary nucleus; pos to pyramids
- CN12: groove between olives & pyramids
- CN9-11: groove between olives & ICP
- ICP: connect to cerebellum, pos to olives
POSTERIOR SURFACE
- gracile tubercle: swelling produced by gracilis ucleus
- cuneate tubercle: lat of gracile
- has lower floor of 4th ventricle
BRAINSTEM: Medulla - Table
pyramids - cavity (1), nuclei (4), motor (2), sensory (4)
med lemniscus - cavity (1), nuclei (5), motor (1), sensory (7)
olives/ICP - cavity (1), nuclei (8), motor (1), sensory (5)
inf to pons - cavity (1), nuclei (2)
pyramids
- cavity: central canal
- nuclei: nucleus cuneatus, nucleus gracilis, spinal of CN5, accessory
- motor: corticospinal, pyramids
- sensory: LSTT, antpos spinocerebellar, spinal tract of CN5
med lemniscus
- cavity: central canal
- nuclei: nucleus cuneatus, nucleus gracilis, spinal of CN5, accessory, CN12
- motor: pyramids
- sensory: LSTT, antpos spinocerebellar, spinal tract of CN5, decussation of medial lemniscus, fasciculus
olives
- cavity: 4th ventricle
- nuclei: CN8-10, CN12, spinal of CN5, inf olivary nucleus, nucleus ambiguus, nucleus of solitary tract
- motor: pyramids
- sensory: LSTT, ant spinocerebellar, spinal tract of CN5, medial lemniscus, tectospinal tract
inf to pons
- cavity: 4th ventricle
- nuclei: CN8
BRAINSTEM: Medulla
level of olives
- pontine nucleus: receive from, send via
- ICP: level/lat to (?), has what
- RF: where to what
inf to pons
- nuclei (2)
clinical
- arnold: structure + CN, type of hydrocephalus
LEVEL OF OLIVES
- pontine nucleus: receive from cerebral cortex, send via ant external arcuate fibers
- ICP: lateral to 4th ventricle, has nucleus of spinal tract of CN5
- reticular formation: pos to olives
INF TO PONS
- has lateral vestibular, both antpos cochlear now visible
CLINICAL
- arnold chiari: internal hydrocephalus; 4th ventricle, last 4 CN
BRAINSTEM: Pons
trapezoid body - divides (ant/pos), nuclei (2)
ant surface
- cave/vex, CP, groove
- CN: motor vs. sensory (med/lat + size)
- CN (3): between
pos surface
- visual, shape, ventricle, CP
- median sulcus: divides
- median eminence: describe, where, bounded, expand & form (1)
- facial colliculi: CN (2)
- substantia ferruginea: color, what/where
- area vistibuli: by/from, where
- trapezoid body: divides pons into tegmentum (pos) & basal (ant); has trapezoid & cochlear nuclei
ANTERIOR SURFACE
- convex, has MCP, has basilar groove for basilar a.
- CN5: motor (smaller medial), sensory
- CN6-8: between pons & medulla
POSTERIOR SURFACE
- hidden by cerebellum, triangle
- has upper floor of 4th ventricle, SCP
- median sulcus: divides pons
- median eminence: elevation; lateral to median sulcus, bounded by sulcus limitans, expand inferiorly & form facial colliculus
- facial colliculi: CN7 wind around CN6 nucleus
- substantia ferruginea: bluish superior part of limitans
- area vestibuli: from vestib nucleus; lat to limitans
BRAINSTEM: Pons
internal structures
- medial lemniscus: with
- facial nucleus: where to ML
- median longitudinal fissure: connects (2.3)
- vestib nucleus
- pontine nucleus: where in pons
clinical
- astrocytoma: epidemiology, structure, sx (4)
- pontine infarct: artery, paramedian (3), lateral pontine (4)
INTERNAL STRUCTURES
- medial lemniscus: with spinal & lateral lemniscus
- facial nucleus: lat to med lemniscus
- median longitudinal fissure: connects CN8 to extraocular muscles (CN3,4,6)
- medial vestibular nucleus
- pontine nucleus: in basilar pons
CLINICAL
astrocytoma
- epi: most common tumor in brainstem
- ipsilateral CN & contralateral hemiparesis
- sx: nystagmus, lat rectus, ipsilateral facial weakness
pontine infarct
- basilar a.
- paramedian: corticospinal, MCP, pontine nucleus
- lateral pontine: corticospinal, MCP, medial lemniscus, CN5
