Spasticity is generally caused by damage or disruption to the area of the brain and spinal cord that are responsible for controlling muscle and stretch reflexes. These disruptions can be due to an imbalance in the inhibitory and excitatory signals sent to the muscles, causing them to lock in place.

Where is spasticity most common?

Spasticity can affect muscles in any part of the body, but is most common in leg muscles.

What part of the brain causes spasticity?

Spasticity is a result of disrupted communication between the brain and the muscles. The source of that disruption is usually the cerebral cortex (the region of the brain that controls movement) or the brainstem, where nerves connect the brain to the spinal cord.