Motor Problems Flashcards
Upper motor neurons:
The cell bodies are found in the cortex:
- Most are in the motor cortex (pre-central gyrus). What type of cells are there?
- The rest are in the brain stem. What are these neurons referred to as?
How is the information carried to the LMN?
Where do UMN lesions become LMN lesions?
What is UMN sometimes referred to as?
Pyramidal cells in the motor cortex
Extrapyramidal neurons
Pyramidal (corticospinal and corticobulbar) and extrapyramidal tracts - so both the pre-motor cortex and the brain stem produce tracts
Anterior (ventral) horn cells - LOOK AT PICS OF SPINAL CORD
Pyramidal lesions = UMN lesions
Upper motor neurons:
Corticospinal tract:
> Where do 90% of these tracts lie, laterally or medially?
> Where do they decussate?
> Function
Would you get a contralateral/ipsilateral deficit if there is a:
- Cortical lesion
- Spinal cord lesion
Where do the anterior corticospinal tracts decussate?
What is its function?
Lateral
Medulla
Fine muscle movement, mainly of the limbs
Contralateral deficits - crosses over in medulla
Ipsilateral deficits - already crossed over in medulla
Where it exits the spinal cord
The trunk muscles and posture
So corticospinal tracts > medulla
Anterior corticospinal tract > level of exit at spinal cord
https://teachmeanatomy.info/neuroanatomy/pathways/descending-tracts-motor/
Lower motor neurons:
Where are the cell bodies?
What is classed as LMN lesion?
Anterior horn of the spinal cord or the motor nuclei of the cranial nerves
Anterior horn cells and below Ventral nerve root Peripheral nerves NMJ The muscle
UMN lesions:
Early UMN lesions (e.g. stroke, SAH) are similar to LMN lesions in their presentation. What 2 things present?
When the lesion is more established, what sort of signs do you see?:
- Does anything happen to the muscle bulk?
- Power
- Reflexes - what happens to reflexes, what special reflexes might you see? - 2
- Tone
- Do you get fasciculations?
Reduced tone - floppy
Reduced reflexes - hyporeflexia
Normal bulk
Reduced power
Hypereflexia (Babinski and clonus)
Hypertonia
No fasciculations - that only happens in LMN as the direct nerve on the muscle is affected
UMN lesions:
Pyramidal lesions - why do you get a flexed arms and leg extension?
What else do you get with this?
Extrapyramidal lesions - you get rigidity. How does this differ from spasticity?
Arm extensors weak - flexed arm
Leg flexors are weak - leg extension
BASICALLY THE BACK OF EVERYTHING IN LIMBS ARE WEAK
Spasticity - velocity-dependent hypertonia - you get a catch due to sudden increase in tone.
Rigidity differs from spasticity in that the increased tone remains constant throughout the range of movement of the joint - non-velocity dependent.
SO WITH EXTRAPYRAMIDAL - you get normal UMN signs - RIGIDITY
UMN lesions:
Presentation by location:
Are cortical lesions contra/ipsilateral?
Lesions in the medulla:
- Contra/ipsi
- UMN/LMN sym
Do lesions od cranial nerves cause:
- LMN or UMN sym
- Contra/ipsi
Contralateral sym
Medulla:
Contralateral and UMN
CN:
Ipsi
LMN
UMN lesions:
Presentation by location:
Spinal cord lesions (myelopathy):
- UMN/LMN symptoms below the level of the lesion?
- Are symptoms usually bi/unilateral?
- What may happen the limbs?
- What may you get LMN symptoms at the level of the lesion?
- Causes - list some
UMN symptoms below the level of the lesion
Bilateral
Paraplegia (legs only)
Quadriplegia (all limbs)
Due to LMN cell body or root damage ( Basically anterior horn)
Spinal cord compression Transverse myelitis MS Spinal artery thrombosis Cord vasculitis B12 deficiency Syphilis
LMN lesions:
When the lesion is more established, what sort of signs do you see?:
- Does anything happen to the muscle bulk?
- Power
- Reflexes
- Tone
- Do you get fasciculations?
Reduced bulk - muscle wasting
Reduced power
Reduced reflexes
Reduced tone
You get fasciculations
LMN lesions:
What is radiculopathy?
What are the main symptoms you get?
Referred to as pinched nerve, refers to a set of conditions in which one or more nerves are affected and do not work properly (a neuropathy).
This can result in pain (radicular pain), weakness, numbness, or difficulty controlling specific muscles.
LMN lesions:
What is neuropathy?
What are the main symptoms you get?
What symptoms do you get with NMJ problems?
What symptoms do you get with myopathy?
Peripheral nerves are damaged or diseased.
Weak Hyporeflexia ---- Weakness and normal reflexes - MG Weak or reduced reflexes that improve with repetition - Lambert-Eaton ---- Dystrophy due to wasting Reduced tone Myotonia - slow relaxation after contraction
What conditions would give a mixture of Upper and Lower motor neurone lesions?
MND
Disc degeneration which compresses the cord and a root
Spinal cord lesions in which there is anterior horn cell and/or root damage
Conus medullaris syndrome
Vit B12 deficiency
Proximal weakness:
What is it?
What is distal weakness?
What is global weakness?
The weakness of the hips and shoulders.
The weakness of the distal limbs - elbow, fingers, calves
Proximal + distal weakness
Proximal weakness:
S+S:
If you have weak hips, what might be difficult to do?
If you have weak shoulders, what might be difficult to do?
Hard getting upstairs, from chairs, up hills
Hard reaching up to shelves
Washing hair is hard
Mononeuropathy:
What is it? - look at name
What causes it?
What is mononeuritis multiplex?
Prognosis of mononeuropathy
Damage to a single peripheral nerve
Trauma
Compression
Stretching of the nerve
Multiple, non-contiguous nerves are affected
Most recover but some may need surgical decompression
Polyneuropathy:
What is it?
Causes of sensory polyneuropathies:
- Endocrine condition
- Lifestyle - 1
- Vitamin deficiency - 2
- Kidney issue
Causes of motor polyneuropathies:
- Autoimmune - G
- A type of poisoning
Damage to many peripheral nerves
DM
Alcohol
B12 and folate deficiency
CKD
Guillain-Barre syndrome
Lead poisoning
