A5. Symptoms of upper and lower motoneuron lesion Flashcards
Lower motor neuron
Everything LOWERED
* Less muscle mass
* decreased muscle tone
* decreased reflexes
* downgoing toes
UPper motor neuron
everything UP
* tone
* DTR (deep tendon reflex)
* toes
weakness is found in which motor neuron lesion
both
UMN and LMN lesion
atrophy is found in which motor neuron lesion and why?
-
LMN lesion
*Hypotrophy/atrophy
*Due to no innervation
UMNL
* Initially no atrophy
* Later: diffuse atrophy
fasciculations is found in which motor neuron lesion
LMN LESION
When even more damaged:
fibrillations
compare how are Reflexes in motor neuron lesions
- LMN : decreased reflexes
- UMN lesion: increased reflexes, Hyperreflexia +/- clonus **
-No inhibitory effect on the reflex arc
compare tone in motor neuron lesions
- tone decreased in LMN lesion (Hypotonic)
- tone increases in UMN lesion: Hypertonic
-Velocity-dependent, clasp-knife phenomenon
babinski is found in which motor neuron lesion
UMN lesion
Pos+ Babinski (big toe up)
spastic paresis is found in which motor neuron lesion
UMN lesion
Flexors of upper limbs, extensors of lower limb
flaccid paralysis is found in which motor neuron lesion
LMN lesion
clasp knife spasticity is found in which motor neuron lesion
UMN lesion
what is clasp knife spasticity and where is it most prominent
- spastic limb is passively moved with great resistance
- then suddenly is limb releases becoming very easy to move
- most prominent in muscle groups which are least affected by UM lesion (upper limb flexors, lower limb extensor)
paralysis vs paresis
paralysis= complete loss of voluntary movement of muscle or limb
paresis= muscular weakness due to nerve problems (=partial paralysis)
Clonus definition
rapid dorsiflexion of ankle/foot
→ several involuntary, rhythmic dorsiflexion spasms
muscles involved in UMNL VS LMNL
- UMNL: Large groups
Contralateral/ipsilateral (over/under decussation) - LMNL: Restricted groups, Ipsilateral
Upper motor neuron lesion WHAT IS it
Damage anywhere along the corticospinal (=pyramidal tract) leading to spastic paralysis of the associated muscles
- Most important symptom: Positive pyramidal signs ( Babinski )
-
Ventral corticospinal tract: Trunk & upper leg muscles (posture/locom.)
Lateral corticospinal tract: Distal limb muscles (fine manipulation)
UMNL
Ventral corticospinal tract: VS Lateral corticospinal tract:
muscles affected
-
Ventral corticospinal tract
Trunk & upper leg muscles (posture/locom.) -
Lateral corticospinal tract: Distal limb muscles (fine manipulation)
-Loss of fine movements may occur
Lower motor neuron lesion what is it
Damage anywhere from anterior horn cells of spinal cord to the muscle innervation
(nerve roots, plexuses or peripheral
nerves)
leading to flaccid paralysis of the associated muscles.
- Most important symptom: Visible fasciculations
○ Spasticity define
-occurs due to what lesion
- resistance in one direction
(e.g flexion of arms, but not extension), - due to lesions of the
corticospinal/pyramidal tract. - Velocity-dependent.
○ Rigidity define
-where is the lesion?
- resistance in all directions (e.g cogwheel-, lead-pipe rigidity)
- due to lesions of extrapyramidal tract.
- Not velocity-dependent.
which is velocity dependent spasticity or rigidity
spasticity is velocity dependent
Fasciculations define
Visible twitching of motor unit of muscle due to spontaneous firing of
action potentials from damaged nerve
Fibrillations define
when is it seen?
Non-visible twitching of individual muscle fibers when nerve is even more
damaged - only seen on electromyogram
Upper motoneuron lesion is caused by damage to the
upper motoneurons and their axons in the cortex, corona radiata, internal capsule, brainstem and the lateral column of the spinal cord
upper motoneuron lesion may be flaccid or spastic depending on
Depending on the
* site of the lesion and
* duration of the paralysis
ower motoneuron lesion is caused by damage to the
bulbar and spinal motoneurons at the level of the cell bodies, axons and neuromuscular synapses.
n addition to the paralysis, its symptoms include decreased or absent deep tendon reflexes, flaccid muscle tone, muscle atrophy, and fasciculation. Pyramidal signs are not present.
