[Repetitive stimulation test on the anconeus muscle for the diagnosis of myasthenia gravis: the mapping of its motor end-plate area].
To map the motor end-plate area of the anconeus muscle and define the best place for positioning the recording electrodes in repetitive stimulation tests (RST) for the diagnosis of neuromuscular transmission disorders.



The compound muscle action potential of the anconeus was recorded after stimulating the motor branch of the radial nerve that innervates it. By analyzing the waveforms registered at each point of the skin we were able to define the motor end-plate area.



The motor end-plate area of the anconeus is a line parallel to the ulna border. The best place for placing the "active" recording electrode is about 2 cm distal to the olecranon and 1 cm lateral to the border of the ulna.



Performing RST in the anconeus muscle is simple and well tolerated. Stimulation of the anconeus almost doesn't move the forearm and the procedure is virtually free of movement artifacts.
Coriolano
Maria das Graças Wanderley S
Md
Universidade Federal de Pernambuco, Recife PE, Brasil. coriolus@uol.com.br
Amorim
Adelmar Afonso de
AA
Lins
Otávio Gomes
OG
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D005542:Forearm / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results