In their review of the effects of surgery on the respiratory muscles Siafakas and co-workers have cited my work incorrectly on two occasions.1 We reported a study of respiratory mechanics after abdominal surgery with measurements of the pressure-volume characteristics of the rib cage and abdomen.2 This report has been cited to support statements on the effects of surgery on gas exchange efficiency of the lung and of general anaesthesia on the thorax. On neither occasion is this citation appropriate. We found evidence that the abdominal muscles were active in patients after abdominal surgery, that this activity was variable, and that it could possibly explain the patterns of movement otherwise considered to represent “diaphragmatic dysfunction”. These observations, along with a short review of the published work …