Carnett's Sign - History

History

This test was first described by John B. Carnett in 1926. The first clear description of anterior abdominal wall pain arising from structures other than the underlying viscera was Cyriax in 1919. Cyriax considered that pain could be mimicked by lesions that arose from the vertebra, ribs or other associated structure or that they were the result of direct irritation of intercostal nerves. By identifying conditions such as alterations in the normal vertebral curves, minor subluxation of vertebral bodies and pressure on the peripheral portions of the intercostal nerves, he was able to employ various mechanical treatments to correct the abnormalities and relieve his patients’ symptoms. Despite this paper little attention was paid to this problem until Carnett developed his simple clinical test. Carnett thought that lower abdominal pain was commonly caused by the lower six thoracic nerves and wanted to be able to distinguish this origin from that arising from the viscera.