要約

Previously, the diaphragm was thought to be the only important contracting muscle during quiet breathing in humans. Now it is known that also the scalenes and the parasternal intercostals are primary inspiratory muscles, and that during expiration in most body positions except lying down the abdominal muscles and the transversus thoracis muscle (triangularis sterni or sternocostalis muscle) are regularly active, making quiet expiration an active process instead of a purely passive maneuver as was thought in the past. The external intercostal muscles, the levatores costarum longi and breves muscles, the sternocleidomastoid muscle, and the serratus posterior superior and inferior muscles can be regarded as accessory inspiratory muscles. The pyramidalis and internal intercostal muscles are accessory muscles of expiration.
Several neuromuscular disorders can affect respiration. Nowadays, several electrodiagnostic techniques can be applied and can be of great value in more precisely determining the nervous system cause, if present, for respiratory failure or insufficiency. Nerve conduction studies of phrenic and intercostal nerves, and needle as well as surface electromyography of most respiratory muscles, can be performed. To measure central conduction to assess the integrity of the corticospinal tracts, magnetic transcortical and nerve root stimulation can be performed.