Restrictive ventilatory defect (HP_0002091) is a functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus. Also known as: Restrictive deficit on pulmonary function testing, Restrictive deficit on pulmonary function tests, Restrictive respiratory disease, Restrictive respiratory insufficiency, Restrictive respiratory syndrome, Spirometric restriction, Stiff lung or chest wall causing decreased lung volume.