Lecture 7 Flashcards
Anterior corticospinal tract primarily controls _______
axial musckes (neck and trunk), controls muscles bilaterally
Describe charcterics of anterior coticospinal tract
May divide and cross at spinal level
Identify this pathway
anterior corticospinal tract
Describe pathway of anterior corticospinal tract
descends ipsilaterally in anterior column as get to innervated level in SC, may bifurfacate. One side stays ipsilateral and other crosses midlone in white matter (commisural fibers) to activate cell bodies on opposite side
From anterior column, anterior corticospinal tract enter ___
anterior horn
Identify this structure
Internal capsule
Identify this structure
Medulla
Identify this structure
anterior corticospinal tract
Identify this structure
lateral corticospinal tract
Identify this structure
lower motor neuron
Site of origin of anterior corticospinal tract
primary motor cortex and supplementary area
level of termination of anterior corticospinal tract
cervical and upper thoracic cord
function of anterior corticospinal tract
control of bilateral axial and girdle muscles
Describe upper and lower motor neuron for corticobulbar tract
UMN from facial region synapse with LMN in pons
Lower motor nuclei controlling facial expression called facial nuclei, extends as facial nerve (CN VII).
Describe cranial nuclei
Within the brainstem 12 nuclei (cranial nuclei), can have motor or sensory function or autonomic function. If motor function exons extend out to muscle, if have sensory have afferent info coming into cranial nerves. Nerves that project out form cranial nuclei (12 cranial nerves).
Name for cranial nuclei 7
facial nerve
Name for cranial nerve 7
facial nerve
Function of facial nerve
Carries motor neurons that travel to muscle of face responsible for face expression
Facial nerves conisdered like _____
LMN’s, travel from CNS to muscle, same functions as LMN going out from spinal cord out to muscles
Where facial nuclei found
In the pons (left and right side)
Muscles of facial expression innervates by
facial nerve
CN VII travels to ____
ipsilateral facial muscles
How to upper motor neurons of corticobulbar tract travel
UMN travel bilaterally to CN VII for muscles above the eyes (e.g. foehead)
UMN travel contralaterally to CN VII for muscles below eyes: at pons crosses the midloine act on LMN for lower part of face. No ipsilateral inputs for lower part of face
Identify this part of cortex
contralateral primary motor cortex
Identify this part of cortex
ipsilateral primary motro cortex
Identify this
Upper motor neuron
Identify this
pons
Identify this
CN VII
Identify this
Lower motor neuron
Identify this type of injury
Upper motor neuron-type facial weakness
Identify this type of injury
Lower motor neuron-type facial weakness
Weakness on entire side of face (upper and lower neurons)- whats the damage?
Damage to facial nuclei in pons, e.g. with damage to pons on ipsilateral side, or facial nerve (where axons for those muscles are travelling together). Damage on same side as symptoms.
Weakness on lower portion of face (not including upper portions)- whats the damage?
Damage to upper motor neuron e.g. with damage to the cortex or nerve, the LMN remains intact. Some preserved function of upper portions of face because of intact ipsilateral inputs from motor cortex.
Describe facial palsy
unknown origin (viris?), enflamed facial nerve or nucleus, weakness on entire side of face on ipsilateral side of symptoms
Describe organisation of corticospinal and corticobulbar tracts
axons maintain somatotopic organisation
Describe how to test for facial weakness
asking patient to do facial expressions- e.g. squeeze eyes shut or raise eyebrow or smile, gimace
Describe organisation of muscles at level of internal capsule
from anterior to posterior: face, arms, trunks, legs
Describe organisation of muscles at level of midbrain
face most medial, arms, trunk, legs most lateral
Describe what happens with somatotopic organisation of fibres as move down brainstem into spinal cord
As continue from internal capusle to basis pedunculi ribbon of axons rotates, at pons, face gets off, the arms most medial once reach cervical regions, arms which are most medial enter anterior horn, then by the level of the lumbar region, only legs left
Identify the muscles of this region of internal capsule
Leg
Identify the muscles of this region of internal capsule
trunk
Identify the muscles of this region of internal capsule
arm
Identify the muscles of this region of internal capsule
face
Identify the muscles of this region of midbrain
Leg
Identify the muscles of this region of midbrain
trunk
Identify the muscles of this region of midbrain
arm
Identify the muscles of this region of midbrain
face
Identify this muscle
legs and feet
Identify this muscle
trunk
Identify this muscle
arms and hands
Identify this muscle
face
Identify 4 other descending motor tracts that may infleunce lower motor neurons
Rubrospinal tract, reticulospinal tract, vestibulospinal tract. tectospinal tract
where are the origin of other descending tracts
brainstem
Describe rubrospinal tract location
from red nucleus in midbrain to spinal cord
Describe reticoluspinal tract location
from reticular formation (nuclei run through central part of brainstem) to spinal cord
Describe vestibulospinal tract location
from vestibular nuclei to spinal cord
describe tectospinal tract location
from superior colliculus to spinal cord
Identify this
tectum
Identify this
red nucleus
Identify this
medial reticular formation
Identify this
lateral reticular formation
Identify this
lateral and medial vestibular nuclei
Lateral corticospinal tract travels in the _____
lateral column
Site of origin of rubrospinal tract
red nucleus, manocellular division
Site of decussation of rubrospinal tract
ventral tegmental ducussation in midbrain
level of termination of rubrospinal tract
cervical cord
function of rubrospinal tract
movement of the contralateral limbs , faciliates flexor tone and inhibits extensor muscle tone in arms
rubrospinal tract travels in ______
lateral column (primarily to cervical segments)
Identify this tract
rubrospinal tract
Site of origin of vestibulospinal tracts
medial VST: medial and inferior vestibulo nuclei; lateral VST: lateral vestibular nucleus
Nuclei that give rise to vestibular spinal tracts
medial and lateral vestibular nucleus
level of termination of vestibulospinal tract
Medial VST: cervical and upper thoracic cord; lateral VST: entire cord
Function of vestibulospinal tract
medial VST: positioning of the head and neck; lateral VST: balance
Describe lateral vestibulospinal tract location and function
originates from lateral vestibular nucleus at level of pons , ipsilateral to all levels of spinal cord, faciliates extensor muscle tone, inhibition of flexor muscle tone in arms and legs,
Describe medial vestibulospinal tract location and function
orginiates from medial vestibular nuclues in medualla, bi-lateral to cervical and thoracic levels it bifurfactes at level of nucleus, have both reflex and tone activationof axial (trunk) and neck muscles
origin of reticulospinal tracts
pontine and medullary reticular formation
level of termination of reticulospinal tract
entire cord
Function of reticulospinal tract
automatic posture and gait-related movements, modulates reflexes and tone
Where reticulospinal tract travels
ventral column to spinal levels (medial motor nuclei)
Tracts treveling in lateral motor systems
lateral corticospinal tract and rubrospinal tract
tracts traveling in medial motor systems
anterior corticospinal tract, lateral vestibulospinal tracts, and pontine reticulospinal tract
Identify this tract
medial vestibulospinal tract
Identify this tract
tectospinal tract
Identify this tract
Lateral corticospinal tract
Identify this tract
rubrospinal tract
Identify this tract
medullary reticulospinal tract
Identify this tract
pontine reticulospinal tract
Identify this tract
lateral vestibulospinal tract
Identify this tract
anterior corticospinal tract
