Brainstem Flashcards
Four functional groupings
Cranial nerve nuclei
Sensory and motor tracts
Cerebellar circuitry
Reticular formation
Brainstem lesions are often associated w/
CN abnormalities, long tract findings, ataxia, impaired RF function
Upper midbrain
Level of superior colliculi
Oculomotor nucleus
Red nucleus
Reticular formation
Sensory and motor tracts
Lower midbrain
Level of inferior colliculi
Trochlear nucleus
Reticular formation
Sensory and motor tracts
Upper mid Pons
Pons between middle cerebellum peduncles
Superior and middle peducnlcles
Reticular formation
Sensory and motor tracts
Lower pons
Cerebellar peduncles
Abducens Facial Vestibular nuclie Reticular formation Sensory and motor tracts
Upper medulla
Hypoglossal nucleus Nucleus ambiguous and solitaries CN X Inferior cerebellar peduncle Vestibular nuclei Reticular formation Sensory and motor tracts
Lower medulla
Dorsal columns and nucleus Medial meminiscus Internal accurate fibers Reticular formation Sensory and motor tracts
Upper reticular formation
Midbrain and upper pons work w/ diencephalic nuclei.
Alert, conscious state in forebrain
Lower reticular formation
Lower pons and medulla work w/ CN nuclie and SC.
Autonomic, motor, flex functions
Regulation of LOC
RF
Cortical and subcortical networks that carry out major functions of consciousness (medial and lateral frontoparietal association cortex w/ upper BS and diencephalon)
Lesion leading to a coma
Upper brainstem RF
Bilateral regions to cortex
Bilateral lesion of thalamus
Coma
Unarousable unresponsiveness in which pt lies w/ eyes closed.
Minimum duration of 1 hour.
Many brainstem reflexes, meaningful responses by cortex are absent
Not generally permanent
Brain death
Extreme and irreversible form of coma
Nor forebrain or brainstem fx
EEG is a flat pattern
NonREM sleep
Medulla
Beginning of sleep cycle
REM sleep
Pons
Inhibit muscle activity
Dreaming occurs
Respiration
Medulla
Caudal nucleus solitaries
Pre-botzinger complex
Inspiration - phrenic C3-5
Insp and exp - thoracic segments
HR and BP
Multiple levels
Caudal nucleus solitarius from baroreceptors
Extend to PS and symptoms oreG neurons in BS and SC
Decorticate posturing
Abnormal flexor posturing
Lesion to midbrain or above
Decerebrate posturing
Abnormal extensor posturing
Lesion below midbrain
Pseudobulbar affect
Abnormal, frequent, uncontrollable outbursts of crying or laughing
Brainstem lesion
Pontomedullary RF : reflexes
Coughing Hiccupping Sneezing Yawning Shivering Gagging Vomiting Swallowing Laughing Crying
Blood supply - midbrain
PCA
Blood supply - upper and lower pons
Basilar artery
Blood supply - medulla
Vertebral artery
Blood supply - primary blood supplier
Anterior spinal artery
Blood supply - medulla (all)
Vertebral, anterior spinal (medial), PICA (lateral)
Blood supply - lower pons
Basilar, AICA
Blood supply - upper pons
Basilar, superior cerebellar
Blood supply - midbrain (all)
PCA, superior cerebellar
Practice filling in
Vascular territories
Medial midbrain syndrome (Weber’s)
Midbrain basis
PCA and top of basilar
Oculomotor motor nerve fascicles, cerebral peduncle
Ipsilateral oculomotor pasly, contralateral hemiparesis
Medial pontine syndrome (fovilles)
Medial pontine basis and tegmentum
Basilar, ventral and dorsal territories
Corticospinal and corticobulbar tract—> Contra face, arm, leg weak, dysarthria;
facial colliculus—> ipsilateral face weak and horizontal gaze palsy
medial lemniscus—> contra decreased position and vibration sense
Locked in syndrome
Bilateral infarct to ventral pons (basilar artery)
Bilateral CTS and CBT
Affects horizontal eye movements
Vertical eye movements and eyelid elevation spared
Lateral medullary syndrome (wallenberg’s)
Lateral medulla
Vertebral artery
Inferior cerebella peduncles, vestibular nuclei —> ipsilateral ataxia, vertigo, nystagmus nausea
Trigeminal nucleus and tract __> ipsilateral facial decreased pain and temp sense
ST tract —> contra body decreased pain and temp sense
Descending symp fibers 00> ipsilateral horner’s
Nuclues ambiguus—> hoarseness, dysphasia
Nucleus solitarius —> ipsilateral decreased taste
Medial medullary syndrome
Medial medulla
Paramedics branch of cerebral and anterior spinal
Pyramidal tract —> contra arm or leg weak
Medial lemniscus —> contra decreased position and vibration
Hypoglossal nucleus and exiting CN XIII fascicles —> is pi tongue weak
5Ds
Diplopia Dizziness Drop attack Dysarthria Dysphagia
3Ns
Nausea
Numbness/tingling
Nystagmus
