brainstem

prosencephalon

cerebral cortex and thalamus

diencephalon

all structures with word thalamus

telencephalon

cerebrum, white matter, basal ganglia, limbic structures

rhombencephalon

hindbrain, older part
includes brainstem and cerebellum

metencephalon

pons and cerebellum

myelencephalon

medulla

mesencephalon

midbrain, between prosencephalon and rhombencephalon

tracts in brainstem

corticobulbar, corticoreticular, corticopontine, corticospinal

reticular formation

distributed mesh nerves, tegmental portion of brainstem
adjusts general level of activity throughout nervous system, neuromodulatory effect

lateral zone

arousal, integration of all sensory info

medial zone

vital functions, somatic motor activity (reticulospinal tracts, postural control, muscle tone, reflex modulation)

midline zone

modulate pain/nociception, somatic motor activity, awareness (raphe nucleus - sleep onset)

midbrain borders

rostral: diencephalon, line from post commissure to edge of mammillary bodies
caudal: pons-midbrain junction

basis pedunculi (basilar midbrain)

cerebral peduncles/crus cerebri: descending tracts from cortex
substantia nigra: part of basal ganglia network, important for PD patho, site of cell bodies associated with dopamine production

midbrain tegmentum

ascending sensory tracts, superior cerebellar peduncles, red nucleus, pedunclopontine nucleus, periaqueductal gray, CN nuclei

superior cerebellar peduncles

primarily efferent to cerebral cortex from cerebellum

red nucleus

input from cerebellum and cerebral cortex, output from cerebellum, spinal cord, and reticular formation

pedunclopontine nucleus

part of basal ganglia network, initiation/termination of movement, rigidity with PD

periaqueductal gray

surrounds cerebral aqueduct
pain modulation system, involved in coordination of somatic and autonomic reaction to pain/emotions, vocalization during laugh/cry
connected to raphe nuclei

midbrain tectum

pretectal area: pupillary reflex
colliculi: sup and inf

midbrain cranial nerves

oculomotor, trochlear, and mesencephalic nucleus of CN V

superior colliculus

part of visual system, visual attention and eye movement

corticopontine tract

cerebral cortex to pontine nuclei

corticobulbar tracts

cerebral cortex to brainstem nuclei

inferior colliculus

termination of lat lemniscus, part of auditory pathway to med geniculate lemniscus

midbrain blood supply

dorsal midbrain: PCA and SCA
ventrolateral: PCA and SCA
medial region: BA, PCA, Pcomm, SCA

pons borders

rostral: rostral edge of basilar pons
caudal: pons-medulla junction

pons general function

process motor info from cerebral cortex and forward it to cerebellum

corticopontine tracts

corticopontine → pontine nuclei → pontocerebellar fibers cross midline → MCP → cerebellum

basilar pons

descending tracts, pontine nuclei, pontocerebellar axons (cross midline)

tegmental pons

sensory tracts, reticular formation, autonomic pathways, MLF, CN nuclei (V main sensory and motor, VI, VII)

middle cerebellar peduncle

pontine nuclei axons cross midline and enter cerebellum

trigeminal lemniscus

brings info from trigeminal sensory nuclei in STTN and main sensory to thalamus, contralat from nucleus

descending sympathetic tract

upper motor control for sympathetics, info from cerebrum to thorax

juxtarestiform body

inferior cerebellar peduncle with restiform body, vestibulocerebellar fibers

internal genu of facial nerve

bend around abducens nucleus

superior olivary nucleus

auditory system

trapezoid fibers

connect 2 sup olivary nuclei to help with determination of sound, where auditory info becomes bilat
decussating axons from cochlear nuclei → form lat lemniscus → midbrain

pons blood supply

anterior medial: BA branches
posterior lateral: BA and SCA rostral, BA and AICA caudal

medulla borders

rostral: pons
caudal: level of foramen magnum

medulla function

coordinate cardiovascular, respiratory, swallowing, visceral, head movement

medulla cranial nerves

VI, VII, VIII, IX, X, XI, XII

olive

external anatomy superficial to inferior olivary nucleus

cuneate and gracile tubercles

place of DCML 1st connection/crossing
cuneate: UE, more lat
gracile: LE, more med

tuberculum cinereum

overlies STTN, bump on lat medulla

postolivary sulcus

location of CN IX, X, XI

MLF

coordination of eye movement
descending part in medulla, coordinates eye/head movement via connection between vestibular nuclei and nuclei that control head movement, med vestibulospinal tract

solitary tract and nucleus

visceral and taste sensory info (CN VII, IX, X)

area postrema

floor of 4th ventricle, increased pressure here can lead to nausea/vomiting

inferior olivary nucleus

receives input from most motor areas, projects to contralat cerebellum

pyramids

in medulla, corticospinal pathway

caudal medulla

level of sensory decussation

arcuate fibers

DCML fibers crossing midline

medial lemniscus orientation

begins vertical, becomes horizontal, ends in a diagonal in midbrain
UE always stays medial

medulla blood supply

pyramids and midline: VA and ASA
lat and post: VA, PICA, PSA

medulla medial vascular insufficiency

can lead to contralat hemiparesis, contralat somatosensory loss, ipsilat tongue weakness, may have weakness head and neck mvmt but less affected due to bilat info

rostral midbrain medial lesion

most common midbrain stroke
contralat loss of sensation, contralat paresis body and lower face, ipsilat CN III loss of function
red nucleus and MLF also involved

caudal pons lateral lesion

2nd most common brainstem stroke
ipsilat loss P and T face, contralat loss P and T body, ataxia, ipsilat Horner’s syndrome, ipsilat CN VII and VIII loss of function

rostral medulla medial lesion

contralat weakness, contralat loss DT, ipsilat tongue weakness

rostral medulla lateral lesion

Wallenberg’s, VA/PICA/PSA
contralat: body P and T
ipsilat: ataxia, vertigo, eye mvmt disorders, nausea, taste, hoarseness, dysphagia, Horner’s syndrome, P and T face, vagal loss of function

Horner’s syndrome

ptosis, miosis, anhidrosis

caudal medulla posterior lesion

PSA vascular insufficiency
ipsilat loss DT, ipsilat loss P and T face