Definition: A form of spasticity in which the legs suddenly straighten into a stiff, extended position. These spasms usually last for several minutes.
This type of spasm is fairly common in multiple sclerosis (MS). Extensor spasms are usually not painful, but can be forceful enough to make people fall out of their wheelchairs or beds. They often occur in the morning as people are getting out of bed or right after getting up.
