Cortico Bulbar, and other pathways Flashcards
an infarction of the posterior limb of the internal capsule damages the
corticospinal and corticobulbar fibers, and somatosensory systems
damage to corticospinal tract in infarction of internal capsule causes
contralateral upper motor neuron syndrome
infarction of internal capsule and damage to somatosensory causes
contralateral sensation losses
damage to corticobulbar fibers that project to hypoglossal nucleus causes
contralateral deviation of the tongue during protrusion
damage to corticobulbar fibers projecting to the contralateral paramedian PPRF in the caudal pons causes
deviation of both eyes towards the lesion
PPRF receives
bilaterally equal tonic innervation
bilateral equal tonic innervation makes it possible to
look straight forward
if PPRF is lost the tonic innervation
of the other side is unopposed causing deviation of eyes towards the side of the damaged upper motor neuron
damage to the corticobulbar fibers innervating the facila nucleus causes
contralateral facial paralysis
the upper facial nucleus receives
bilateral innervation from the ventrolateral primary motor cortex
the lower facial nucleus receives
contralatera projections so in a unilateral central facial lesion the patient will still be able to wrinke the forehead
in a peripheral facial lesion,
the facial nerve itself is damaged and both upper and lower facial muscles are paralyzed
Red Nucleus is located in the
middle portion of the midbrain
Red nucleus receives
exicitatory connections from the ipsilateral motor cortex and from the contralateral cerebellar nuclei.
end of the rubrospinal tract
excitatory synapes of alpha and gamma motor neurons
route of the rubrospinal tract
axons of the red nuclear efferents decussate in the midbrain. Rubrospinal axons descend through the lateral brainstem and anterior horn of spinal cord and end on alpha and gamma motor neurons.
most rubrospinal fibers innervate
neurons of arm muscles
each red nucleus primarily facilitates
voluntary flexion of the muscles of the contralateral arm.
rubral influences on lower limb
minimal
start of medullary(lateral) Reticulospinal tract
reticular neclei in the medula which receive bilateral cortical input from corticoreticulofibers and somatosensory projections through the spinoreticular tract
lateral medullary Reticulo Spinal nuclei receives
Bilateral cortical input from the cortico reticulofibers and somatosensery projections from the spinoreticular tract
the spinoreticular tract is collaterals of
the anterolateral system