Muscle Stiffness & Rigidity

Muscle stiffness can indicate Parkinson's disease (cogwheel rigidity), MS (spasticity), ALS (upper motor neuron involvement), or inflammatory myopathies. The type of stiffness helps differentiate conditions.

Body System: Neuromuscular

Related Diseases

• Parkinson's Disease — Rigidity (cogwheel or lead-pipe type) is a cardinal motor feature caused by basal ganglia dysfunction.
• ALS — Upper motor neuron involvement causes spasticity with increased reflexes and clonus.
• Multiple Sclerosis — Spasticity from corticospinal tract demyelination affects 60-80% of MS patients.

Related Compounds

• Levodopa
• Riluzole

Frequently Asked Questions

What is the difference between rigidity and spasticity?

Rigidity (Parkinson's) is velocity-independent — resistance to passive movement is constant throughout range of motion. Spasticity (MS, ALS) is velocity-dependent — increases with faster passive movement. Rigidity responds to levodopa; spasticity responds to baclofen, tizanidine, or botulinum toxin.