Neuroanatomy-ENC Flashcards
Into what 3 segments are the medulla, pons and midbrain further divided?
Tectum (“roof”, dorsal aspect)
Tegmentum (ventral aspect)
Basis (most ventral aspect of tegmentum)
Which artery or arteries supply the medulla?
Branches of the vertebral arteries, PICA, anterior and posterior spinal arteries
Which ascending pathways are present in the medulla?
Dorsal columnar (medial lemniscal), spinothalamic, spinoreticular, and spinocerebellar
Which descending pathways are present in the medulla and what functions do they mediate?
- Corticospinal tract (motor)
- Descending spinal tract of CN V
- Medial longitudinal fasciculus (gaze and head movements.
- Tectospinal tract (neck and trunk movements in response to visual stimuli)
What fibers do the inferior cerebellar peduncles contain?
Fibers efferent from spinal cord and medulla to cerebellum, and crossed olivocerebellar fibers
Which CN nuclei are housed within the medulla, and what functions do they mediate?
Hypoglossal nucleus (motor to tongue), dorsal motor nucleus of X (parasympathetic innervation of viscera), solitary tract and nucleus (taste and visceral sensory to VPM of thalamus.
How is the homunculus organized in the medullary medial leminscus?
Cervical sensory info is dorsal/posterior to sacral info.
Occlusion of what artery or arteries leads to medial medullary syndrome?
Vertebral branches or the anterior spinal artery
What are the symptoms of medial medullary syndrome?
Contralateral hemiparesis (ipsilateral pyramid), contralateral sensory deficits (medial lemniscus), ipsilateral paralysis and atrophy of tongue muscles (hypoglossal nerve or nucleus)
Occlusion of what artery leads to lateral medullary (Wallenberg’s) syndrome?
Vertebral branches (most commonly) or PICA.
What are the symptoms of Wallenberg’s syndrome?
- Loss of pain and temperature sensation over contralateral body (spinothalamic tract).
- Loss of pain and temp over ipsilateral face (spinal trigeminal tract).
- Hoarseness and dysphagia (nucleus ambiguous)
- Ipsilateral Horner’s (descending sympathetics)
- Possible vertigo, abnormal eye movements, and ipsilateral cerebellar deficits (inferior cerebellar peduncle and adjacent vestibular nuclei).
Occlusion of what artery or arteries lead to Weber’s syndrome?
Branch of the PCA.
What gross structure is damaged in Weber’s syndrome?
Cerebral peduncle
What are the symptoms of Weber’s syndrome?
- Contralateral spastic paresis (corticospinal fibers)
2. Ipsilateral ptosis, pupillary dilation, and lateral strabismus (occulomotor nerve)
Which artery or arteries supply the pons?
Basilar artery and its branches (paramedian and circumferential branches), with some contribution from AICA and SCA.
Which structures are contained within the basis pontis?
Corticospinal fibers, pontine nuclei, pontocerebellar fibers
Which neurotransmitter is contained within the raphe nucleus?
Serotonin
How is the homunculus oriented in the pontine medial lemniscus?
The feet are represented laterally, with the cervical sensory input represented medially.
Which artery or arteries supply the midbrain?
PCAs with some contribution from the basilar artery branches and the SCAs
Which 3 important structures are contained within the base of the midbrain?
Crus cerebri (includes corticospinal, corticobulbar, and corticopontine fibers), substantia nigra and cerebral peduncle
To what structure does the substantia nigra send efferent dopaminergic fibers?
Striatum
What fibers are contained within the cerebral peduncel?
Descending corticospinal and corticopontine fibers
Which neurotransmitter is contained within the locus ceruleus?
Norepinephrine
Which fibers are contained within the superior cerebellar peduncle?
Efferent fibers from the cerebellum to the red nucleus and spinocerebellar tracts
What are the names of the phylogenetic segments of the cerebellum and what are their roles?
- Archicerebellum (contains flocculus and nodulus, plays a role in posture, balance and eye movements)
- Paleocerebellum (lower limb movements and speech)
- Neocerebellum (limb coordination)
What are the cerebellar glomeruli?
Multiple synaptic contacts between mossy fibers with Golgi and granule cells that occur in the granular layer
What are the 3 cytoarchitectural layers of the cerebellar cortex?
An outer molecular layer, a Purkinje cell layer, and an inner granule cell layer
Where do climbing fibers originate?
In the contralateral inferior olivary nucleus
Where do mossy fibers originate?
Deep cerebellar nuclei, vestibular nuclei, the spinal cord, and the cerebellar cortex
Which peduncle is primarily efferent?
Superior cerebellar peduncle
Which CN emerges near the superior cerebellar peduncle?
CN IV
Which peduncle contains only afferent input?
Middle peduncle
Which fibers travel through the inferior cerebellar peduncle?
Input: posterior spinocerebellar tract, cuneocerebellar tract, vestibulocerebellar tract, trigeminocerebellar tract, olivocerebellar tract.
Output: fibers from deep cerebellar nuclei terminating in contralateral red nucleus or contralateral thalamic motor nuclei (ventral lateral and ventral anterior)
What are the alternate names for the cerebellar peduncles?
Superior is brachium conjunctivum
Middle is the brachium pontis
Inferior is the corpus restiform or restiform body
Damage to the midline cerebeullum causes what deficit?
Postural instability
Damage to the lateral cerebellum causes what deficit?
Limb ataxia
Damage to the flocculus causes what deficit?
Difficulty with eye movements (poor pursuit and voluntary eye movements)
The thalamus is divided into 3 major nuclear masses (anterior, medial, lateral) by what white matter bundle?
Internal medullary lamina