Brain Stem Flashcards
What CN arrise from Midbrain
CN 3 and 4
(Oculomotor and Trochlear)
What CN arrise from Pons
CN 5, 6, 7, and 8
(Trigeminal, Abducens, Facial, and Vestibulocochlear)
What CN arrise from Medulla
CN 9, 10, and 11
(Glossopharyngeal, Vagus, and Hypoglossal)
CN 53 (Mandibular) lesion results in
Jaw deviation toward weak side
Trigeminal neuralgia: Intractable pin in V2 or V3 territory
Medial lemniscus contains
Axons from cell bodies found in the dorsal column cuclei (gracilis and cuneatus)
Medial Lemniscus found in
Caudal medulla
Ipsilateral Horner syndrome is a lesion of
Descending hypothalamic fibers
Medial Longitudinal Fasciculus (MLF) are
fiber bundle interconnecting centers for:
Horizontal gaze
Vestibular Nuclei
CN 3, 4, and 6
MLF lesion produces
Internuclear ophthalmoplegia and disrupt the vestibulo-ocular reflex
Olivary nuclei send
Climbing fbiers into the cerebellum from the caudal medulla to the inferior cerebellar peduncle
Solitary nucleus carries
all general and special visceral afferent fibers of CN 7, 9, and 10
Includes:
- Taste
- Cardiorespiratory
- GI sensations
Nucleus ambiguus is
a column of large motoneurons that is situated dorsal to the inferior olives
VPM relays what to cortex
Touch, pain and temperature via CN 5
Taste via CN 7 and 9
Inferior colliculus send auditory information to
The medial geniculate body of the thalams
Path of auditory system
- Cochlear nucleus (in pons) cross at the Trapezoid body (in pons) then connect to Superior Oivary Nucleaus (In pons)
- Then travel to Lateral lemniscus (in midbrain) to the inferior colliculus (in midbrain)
- Then travel to Medial geniculate body (in Thalamus)
- Then to Superior Temporal Gyrus
Lesion of Vestibular nuclei or N results in
Vestibular nystagmus with a slow deviation of the eyes toward the lesion and fast correction back
Ménière disease
Abrupt, recurrent attacks of vertigo lasting minutes to hours accompanied by deafness or tinnitus and is usually in 1 ear
Due to distention of fluid spaces in cochlear and vestibular parts of labyrinth
Horizontal gase controlled by
Frontal eye field (contralateral gaze)
Paramedian Pontine Reticular Formation (Ipsilateral gaze)
Anterior inferior cerebellar artery supplies
Lateral pons
Superior cerebellar artery supplies
Lateral pons
Posterior inferior cerebellar artery supplies
Lateral medulla
Anterior spinal artery supplies
Medial medulla
Posterior cerebral artery supplies
Medial medbrain
Medial medullary syndrome leads to lesion of
- Hypoglossal N: ipsilateral paralysis of half the tong, tongue deviates toward side of lesion
- Both Medial Lemniscus: contra deficit of proprioception and touch, pressure and vibration
- Corticospinal tract: contra spastic hemiparesis of both limbs
Medial medullary syndrome is a lesion of
Anterior Spinal Artery
Lateral medullary syndrome is lesion of
PICA (Wallenberg Syndrome)
Lateral medullary syndrome damages
- Inferior Cerebellar peduncle: Ipsilateral limb ataxia
- Vestibular nuclei: Vertigo, nausea/vomiting, nystagmus (away from lesion)
- Nucleus ambiguus: ipsilateral paralysis of larynx, pharynx, palate
- Spinal N. 5: ipsilateral pain/tem loss (face)
- Spinothalamic tract: contralateral pain/tem loss
- Descending hypothalamic: ipsilateral Horner
Medial Pontine Syndrome is due to occlusion of
Paramedian branches of basilar artery
Medial Pontine syndrome affects
- Corticospinal tract: contra spastic hemiparesis
- Medial lemniscus: contra loss of tactile/position/vibration sensation
- Fibers of CN 6: Medial strabismus
Lateral Pontine syndrome is occlusion of
AICA
Lateral Pontine Syndrome affects
- Middle cerebellar peduncle: ipsilateral ataxia
- Vestibular nuclei: vertigo, nausea, vomiting, nystagmus
- Facial nucleus and fibers
- Spinal trigeminal nucleus/tract: ipsilateral pain/temperature loss of face
- Spinothalamic tract: contra pain/temperture loss
- Cochlear nucleus and fibers (CN 8): ipsilateral hearing loss
- Descending hypothalamic: ipsilateral Horner syndrome
Dorsal Midbrain Syndrome AKA
Parinaud syndrome
Dorsal Midbrain syndrome due to
Tumor in Pineal region
Dorsal midbrain syndrome affects
Superior colliculus/pretectal area: paralysis of upward gaze
Cerebral aqueduct: noncommunicating hydrocephalus
Medial midbrain syndrome AKA
Weber syndrome
Medial medbrain syndrome is due to occlusion of
Branches of PCA
Medial midbrain syndrome affects
- CN3 fibers: ipsilateral oculomotor palsy (lateral strabismus, dialted pupil, ptosis)
- Corticospinal tract: contra spastic hemiparesis
- Corticobulbar tract: contra hemiparesis of lower face
What degenerates in Alzheimers disease
Neurons of both raphe and locus caeruleus
Raphe nuclei synthesize
Serotonin
Locus caeruleus synthesize
Norepinephrine
Pain modulation occurs in
Periaqueductal gray
