A method for locating surface electromyography electrodes on the flexor carpi ulnaris.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Kinesiology

Background:

• The flexor carpi ulnaris (FCU) muscle is crucial for wrist flexion and ulnar deviation, widely used in surface electromyography (sEMG) for clinical and human-machine interface applications.
• Accurate sEMG electrode placement is vital due to small signal amplitudes and susceptibility to noise and crosstalk, yet no standardized method exists for the FCU muscle.

Purpose of the Study:

• To develop and validate a systematic, objective method for locating sEMG electrodes on the flexor carpi ulnarismuscle.
• To improve the consistency and reliability of sEMG data acquisition from the FCU muscle.

Main Methods:

• A novel technique was developed using palpation of the pisiform bone and humeral medial epicondyle to define the FCU muscle line.
• sEMG signals were recorded from three sites on the FCU muscle belly in both arms of 10 participants.
• Signal-to-noise ratio (SNR), mean absolute value (MAV), and frequency spectrum were analyzed to assess electrode placement efficacy.

Main Results:

• An electrode placement at 80% of the distance from the pisiform bone yielded the highest median SNR and MAV across participants.
• The proposed method demonstrated improved signal quality compared to subjective palpation techniques.

Conclusions:

• A systematic method for FCU sEMG electrode placement, based on anatomical landmarks, is presented.
• This technique reduces reliance on practitioner experience, offering a more consistent and reliable approach for clinical and engineering applications.