spasticity

This term describes a specific neurological dysfunction where muscles remain continuously contracted. It is primarily used in clinical settings to describe the physical manifestation of upper motor neuron lesions, creating a sensation of rigidity and resistance to passive movement. As an uncountable noun, it refers to a medical state or quality rather than a discrete object. It does not have a plural form in standard medical usage, as it describes a condition of the neuromuscular system rather than individual instances of a disease.