L06 Motor Pathways Flashcards
is the lower motor neuron body in the CNS or PNS?
CNS
is the axon of the LMN in the CNS or PNS?
PNS
name 4 major inputs from the CNS that a LMN receives input from?
vestibular nuclei
reticular formation
cerebral cortex (major)
red nucleus
which side do LMNs innervate?
ipsilateral
where are the LMNs in the spinal cord?
ventral horns
where are the LMNs in the brainstem?
discrete nuclei that form the bodies of the cranial nerves
a patient presents with hyporeflexia. where is the lesion?
LMN
a patient presents with hyperreflexia. where is the lesion?
UMN
biceps tendon spinal segment innervation?
C6
triceps tendon spinal segment innervation?
C7
patellar tendon spinal segment innervation?
L4
achilles tendon spinal segment innervation?
S1
name symptoms of LMN lesions
ipsilateral weakness hyporeflexia flaccid paralysis atrophy (lack of tropins from nerves) fasciculations (early onset)
role of the vestibulospinal tract?
balance/equilibrium
role of the reticulospinal tract?
gait
role of the rubrospinal tract?
upper limb flexors
role of the corticospinal tract?
voluntary control of skeletal muscle
UMNs are modulated by which parts of the brain?
basal nuclei and cerebellum, via thalamus.
function of the lateral corticospinal tract?
skilled asymmetric limb movement
where do axons of the UMNs in the corticospinal tract synapse?
in the lower cervical and lumbosacral enlargements. innervate distal limb musculature for fine motor skills.
name the path of an UMN from cortex to spinal cord
cortex corona radiata internal capsule cerebral peduncles pyramids decussation of the pyramids lateral corticospinal tract in lateral column
name symptoms of UMN lesions
contralateral hemiplegia if in brain, ipsilateral if in spinal cord. hyperreflexia atrophy (disuse) no fasciculations positive babinski's sign
lesion in CN IV nucleus affects which side?
contralateral
lesion in CN IV nerve affects which side?
ipsilateral
lesion in cranial nerve nuclei affects which side?
ipsilateral (except IV)
babinski’s sign tests for what?
UMN lesion
the corticobulbar tract includes motor for which cranial nerves?
V, VII, IX, X, XI, XII
which cranial nerves in the corticobulbar tract are controlled bilaterally?
V, IX, X
effect of unilateral LMN lesion in the masticator nucleus (V3)?
ipsilateral defect
weakness in muscles of mastication
effect of unilateral UMN lesion in the masticator nucleus (V3)?
little to none. (bilateral control)
effect of unilateral LMN lesion in the nucleus ambiguus (IX, X)?
paresis of vocal cords, soft palate, larynx, pharynx
effect of unilateral UMN lesion in the nucleus ambiguus (IX, X)?
little to none. (bilateral control)
effect of unilateral LMN lesion in the hypoglossal nucleus (XII)?
paralysis of ipsilateral tongue (points in direction of lesion)
effect of unilateral UMN lesion in the hypoglossal nucleus (XII)?
paralysis of contralateral tongue (points away from side of lesion)
effect of unilateral LMN lesion in the accessory nucleus (XI)?
ipsilateral weakness (shoulder shrug and head turn away)
effect of unilateral UMN lesion in the accessory nucleus (XI)?
contralateral shoulder weakness.
ipsilateral SCM weakness.
effect of unilateral LMN lesion in the facial nucleus (VII)?
ipsilateral facial weakness
effect of unilateral UMN lesion of the facial nucleus (VII)?
eyebrows unaffected. (rostral nucleus controls frontalis and is bilaterally innervated)
contralateral caudal paralysis. (caudal nucleus is contralaterally innervated)
