A5. Symptoms of upper and lower motoneuron lesion

Question 1

Lower motor neuron

Answer 1

Everything LOWERED
* Less muscle mass
* decreased muscle tone
* decreased reflexes
* downgoing toes

Question 2

UPper motor neuron

Answer 2

everything UP
* tone
* DTR (deep tendon reflex)
* toes

Question 3

weakness is found in which motor neuron lesion

Answer 3

both
UMN and LMN lesion

Question 4

atrophy is found in which motor neuron lesion and why?

Answer 4

• LMN lesion
  *Hypotrophy/atrophy
  *Due to no innervation

UMNL
* Initially no atrophy
* Later: diffuse atrophy

Question 5

fasciculations is found in which motor neuron lesion

Answer 5

LMN LESION

When even more damaged:
fibrillations

Question 6

compare how are Reflexes in motor neuron lesions

Answer 6

• LMN : decreased reflexes
• UMN lesion: increased reflexes, Hyperreflexia +/- clonus **
  -No inhibitory effect on the reflex arc

Question 7

compare tone in motor neuron lesions

Answer 7

• tone decreased in LMN lesion (Hypotonic)
• tone increases in UMN lesion: Hypertonic
  -Velocity-dependent, clasp-knife phenomenon

Question 8

babinski is found in which motor neuron lesion

Answer 8

UMN lesion

Pos+ Babinski (big toe up)

Question 9

spastic paresis is found in which motor neuron lesion

Answer 9

UMN lesion
Flexors of upper limbs, extensors of lower limb

Question 10

flaccid paralysis is found in which motor neuron lesion

Answer 10

LMN lesion

Question 11

clasp knife spasticity is found in which motor neuron lesion

Answer 11

UMN lesion

Question 12

what is clasp knife spasticity and where is it most prominent

Answer 12

• 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)

Question 13

paralysis vs paresis

Answer 13

paralysis= complete loss of voluntary movement of muscle or limb

paresis= muscular weakness due to nerve problems (=partial paralysis)

Question 14

Clonus definition

Answer 14

rapid dorsiflexion of ankle/foot
→ several involuntary, rhythmic dorsiflexion spasms

Question 15

muscles involved in UMNL VS LMNL

Answer 15

• UMNL: Large groups
  Contralateral/ipsilateral (over/under decussation)
• LMNL: Restricted groups, Ipsilateral

Question 16

Upper motor neuron lesion WHAT IS it

Answer 16

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)

Question 17

UMNL

Ventral corticospinal tract: VS Lateral corticospinal tract:
muscles affected

Answer 17

• Ventral corticospinal tract
  Trunk & upper leg muscles (posture/locom.)
• Lateral corticospinal tract: Distal limb muscles (fine manipulation)
  -Loss of fine movements may occur

Question 18

Lower motor neuron lesion what is it

Answer 18

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

Question 19

○ Spasticity define

-occurs due to what lesion

Answer 19

• resistance in one direction
  (e.g flexion of arms, but not extension),
• due to lesions of the
  corticospinal/pyramidal tract.
• Velocity-dependent.

Question 20

○ Rigidity define

-where is the lesion?

Answer 20

• resistance in all directions (e.g cogwheel-, lead-pipe rigidity)
• due to lesions of extrapyramidal tract.
• Not velocity-dependent.

Question 21

which is velocity dependent spasticity or rigidity

Answer 21

spasticity is velocity dependent

Question 22

Fasciculations define

Answer 22

Visible twitching of motor unit of muscle due to spontaneous firing of
action potentials from damaged nerve

Question 23

Fibrillations define

when is it seen?

Answer 23

Non-visible twitching of individual muscle fibers when nerve is even more
damaged - only seen on electromyogram

Question 24

Upper motoneuron lesion is caused by damage to the

Answer 24

upper motoneurons and their axons in the cortex, corona radiata, internal capsule, brainstem and the lateral column of the spinal cord

Question 25

upper motoneuron lesion may be flaccid or spastic depending on

Answer 25

Depending on the
* site of the lesion and
* duration of the paralysis

Question 26

ower motoneuron lesion is caused by damage to the

Answer 26

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.