Cervical accessory respiratory muscle function in a patient with a high cervical cord lesion.

The function of the accessory respiratory muscles (ARM) of the neck were studied in a quadriplegic patient suffering from a C2-3 lesion of the cervical spinal cord. Subtotal expiratory paralysis resulted in an essentially complete loss of expiratory reserve volume such that residual volume and functiona residual capacity were equal (RV=FRC). Tidal volume and vital capacity were severely reduced. Being extrinsic to the chest, the ARM of the neck functioned independently of changes in thoracic gas volume; however, their performance appeared posture-dependent, and was less efficient in the sitting position. Despite the fact that the ARM preferentially expanded the upper part of the ribcage, significant V/Q mismatch did not seem to occur. Voluntary use of glossopharynegeal breathing (GPB) greatly enhanced the patient's ventilatory capability. Flow volume data during GPB documented the efficiency of the glossopharyngeal muscles, which function as a positive pressure pump to force air into the lungs.