ABSTRACT
Ventilation is ultimately achieved through the contraction and relaxation of the muscles of the chest wall and diaphragm. They are voluntary muscles of the same general composition as the skeletal musculature. It is therefore not surprising that primary muscle disorders may be complicated by the development of ventilatory insufficiency. Given that many such myopathies are progressive in nature and have no specific treatment, it is unarguable that one of the greatest successes of management in the past 20 years has been the introduction of non-invasive ventilatory techniques which have given enormous benefit with respect to quality of life, together with, in some disorders, a very substantial increase in life expectancy.1
