抄録
An electromyographic study on the abdominal wall muscles in normal adults was performed by the use of surface electrodes after Floyd and Silver with eight-channel electroencephalograph. The subjects employed were 15 healthy adults, 10 males and five females, ranging in age from 17 to 40 years.
Results obtained are as follows:
1. Head raising gives rise to the dominant activity of the rectus in supine posture. When the intra-abdominal pressure is raised in supine posture the action of the oblique muscles, especially of the internal, is clearly observed. The rectus plays a passive role and is only involved when the trunk is flexed at the same time. It is, therefore, evident that there is a close relationship between the intra-abdominal pressure and the internal obliques.
2. When the subjects are at rest in a standing posture, the internal oblique muscles demonstrate a state of slight activity.
The amplitude of this discharge is 50-100 μV. This phenomenon indicates that this continuous activity of the internal obliques is being done as a result of the stretch reflex which the weight of the intra-abdominal viscera provokes on the internal obliques. It seems, therefore, that the internal obliques play an important role as an anti-gravity muscle supporting the intra-abdominal viscera.
