Electromyographic studies on reflex activity of the intercostal and abdominal muscles in cervical cord lesions.

Abstract

In 19 traumatic tetraplegics following fracture dislocation of the cervical spine, the intercostal and abdominal muscles were studied electromyographically. The patients were divided into three groups:1. Patients examined first during the stage of spinal shock and followed up until full reflex activity of the isolated cord developed.2. Patients studied in later stages only (three months to more than four years after injury).3. Patients with unilateral paralysis of the diaphragm.During the stage of spinal shock, action potentials of the intercostal muscles in response to the act of breathing were irregular and of small amplitude and duration; they were detectable in the lower intercostal spaces only.In the stage of fully developed reflex activity of the spinal cord, the electrical response of the intercostals was very striking over a much wider area. Details of their reflex activity are described.Unilateral paralysis of the diaphragm greatly reduced but did not abolish reflex function of the intercostals.The significance of the reflex activity of the intercostal muscles is discussed.