Muscle Tone
tone is passive resistance to movement
Hypertonia
Decreased inhibition of upper motor neurons
spasticity
- suggests upper motor neuron causes
- velocity dependent - going slow doesn't induce it, but going quickly does
- unidirectional (anti-gravity muscles) while rigidity is bi-directional
rigidity
- suggests basal ganglia problems (ie Parkinson's)
- same resistance in all directions
- can be cog-wheeling - likely due to concurrent tremor
Hypotonia
Also known as flaccidity
normally due to lower motor neuron disease, but can also follow acute sponal cord injury for a few days (spinal shock)