Professional
Technical
In the Industry Vocabulary Test
motor unit potential
The electrical activity of a single motor unit recorded during needle electromyography examination.
Full Definition
A motor unit potential (MUP) represents the summated electrical activity of all muscle fibers innervated by a single motor neuron, as recorded by needle electromyography. Normal MUPs have characteristic amplitude, duration, and morphology that vary by muscle and age. Pathologic changes include increased amplitude and duration in neurogenic conditions, or reduced amplitude and polyphasic morphology in myopathic processes. MUP analysis is fundamental to distinguishing between neurogenic and myopathic disorders.
Usage
Usage note: May be abbreviated as MUP or MUAP after first use.
In Context
- "Motor unit potentials showed increased amplitude and duration consistent with chronic reinnervation." — EMG report
- "Polyphasic motor unit potentials with reduced amplitude suggested a primary myopathic process." — Electrodiagnostic interpretation
Also known as
MUP
motor unit action potential
MUAP
Don't confuse with
fibrillation potential
positive sharp wave