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Cogwheel rigidity is a characteristic feature of muscular rigidity in Parkinson's disease, where the resistance to passive movement has a distinct pattern reminiscent of a ratchet or cogwheel. This type of rigidity involves a combination of muscle stiffness and intermittent relaxation, leading to a “catching” sensation during movement. It is commonly associated with the basal ganglia dysfunction typical of Parkinson's disease. In contrast, pseudoparkinsonism refers to symptoms that mimic Parkinson's but arise from other causes, spasticity involves a velocity-dependent increase in muscle tone typically associated with upper motor neuron lesions, and muscle atrophy indicates a reduction in muscle mass rather than rigidity. These distinctions clarify why cogwheel rigidity is recognized as a key feature specific to the rigidity encountered in Parkinson's disease.