[Functional analysis of the muscles of the anterolateral wall of the abdomen using electromyocartography].
The purpose of this study was to analyze the function of the superficial muscles of the anterolateral wall of the abdomen in dorsal decubitus by an original technique: electromyocartography. This technique attempts to monitor the individual or inter-subjective variations that complicate quantitative analysis of the overall electromyogram with integration of action potentials. It is shown that relative quantification of the areas explored with respect to the most active area considerably improves the consistency of the results. The most dependable electrode locations for the analysis of the abdominal muscles are determined. From a functional point of view: The rectus abdominis is active in flexion of the cranial portion of the trunk, either alone or in combination with right or left rotation of the trunk. Its activity is less, and predominates in the distal portion of the muscle, in flexion of the caudal portion of the trunk in combination with a 15 degree flexion of the hips. The obliquus internus abdominis, which can be explored only in a single area, is especially active in rotation. The obliquus externus abdominis plays a major role in stabilizing the pelvis when the lower limbs are involved in the movement of the trunk.