Evaluation of a device for the measurement of the evoked tensions of the rectus abdominis muscle

A device was developed to measure the evoked tensions of the rectus abdominis muscle which consisted of a fluid-filled reservoir wedged between the rectus abdominis muscle and a self-retaining retractor. The evoked contractions of the rectus muscle were compared with that of the tibialis anterior muscle in twelve dogs anaesthetised with pentobarbitone. Significantly greater amounts of tubocurarine were required to depress the response to train-of-four stimuli and the twitch tensions of the rectus muscle than the tibialis. The tibialis recovered faster, spontaneously or after neostigmine, than the rectus in eight of the animals; the opposite occurred in the other four. The present device can be useful during surgery for the evaluation of abdominal muscle tension.