Respiratory effects of the scalene and sternomastoid muscles in humans

Alexandre Legrand, Emmanuelle Schneider, Pierre-Alain Gevenois, Andre De Troyer

The studies were performed in seven healthy subjects (5 men and 2 women) 29–49 yr of age. The subjects had normal pulmonary function tests, and their principal anthropometric
characteristics and supine inspiratory capacity are listed in Table 1. They gave informed consent to the procedures, which conformed with the Declaration of Helsinki and were approved by the Ethics Committee of the Brussels School of Medicine.

Five subjects had previously participated in many respiratory experiments and were highly trained in relaxing their respiratory muscles at different lung volumes, but two subjects (subjects 5 and 7) had little prior experience as respiratory subjects. Before the study, these two subjects underwent several practice sessions with pairs of respiratory magnetometers (Norman H. Peterson, Boston, MA) placed on the abdomen and rib cage, during which they were coached to relax their respiratory muscles. At the time of the study, all subjects were able to produce consistent relaxation curves of the chest wall from resting end expiration [functional residual capacity (FRC)] to total lung capacity (TLC).