Electromyographic study of some muscles of the anterolateral abdominal wall.

The authors performed an electromyographic study on behavior of the rectus abdominis and the external and internal oblique muscles on 20 young healthy male volunteers during the performance of many movements of the trunk in the standing and supine positions. Concentric needle electrodes were used in connection with a model Te-4, Teca electromyograph of direct recording on paper. Among the results, stress is put on the fact that the oblique muscles revealed activity when the trunk was twisted to both sides with variable degrees of intensity. The rectus abdominis, that was expected to offer some support to the aponeuroses of the obliques in the trunk torsion, did not show action potentials during the performance of these movements. The action of these muscles in the flexion and extension of the trunk is also reported and discussed.

[Electromyographic analysis of the primary dorsal interosseus muscle of the human hand. I. Movements of the index finger]. / Analyse électromyographique du premier muscle interosseux dorsal de la main humaine. I. Mouvements de l'index.

An electromyographic study of the musculus interosseus dorsalis was performed on the right hand of 25 young adult male right-handed volunteers. The electrodes, simple coaxial needles, were implanted one at the ulnar head and the other at the radial head of the muscle. The muscles were analyzed during free movements of the index and against resistance. The same movements were done in four different positions of the forearm and hand, without variation in the results for each one of the movements. There was no significant difference between the activities of the ulnar head and radial head. During freely performed movements, muscle activity was recorded only during abduction. During movements against resistance, muscle activity was completely nil only during adduction; during the remaining movements, however, moderate (2+), strong (3+) and very strong activity (4+) was recorded.