The integrity of the chest wall and muscular action of the intercostal muscles and diaphragm are necessary to ensure proper ventilation. Though minor deformities may not be functionally significant, gross bony deformities and muscular paralysis impair ventilation and give rise to respiratory embarrassment.
Kyphoscoliosis: Kyphosis is the abnormal curvature of the thoracic spine with convexity directed posteriorly and scoliosis denotes gradual lateral curvature of the thoracic spine, with rotation of the vertebrae in their longitudinal axis. These deformities coexist in most cases. About 1% of the general population is affected and in 25% it is hereditary. Kyphoscoliosis may be congenital or acquired. Acquired Kyphoscoliosis results from poliomyelitis, myopathies, and acquired diseases of the vertebrae. Primary respiratory diseases like pulmonary fibrosis or atelectasis may be associated with this deformity.
The Lung on the narrowed side is compressed. The opposite Lung shows compensatory emphysema. Cardio-respiratory embarrassment may develop in severe Kyphosis where the angle of curvature exceeds 20 degrees and in severe scoliosis with the angle more than 100 degrees. The main finding is reduction of vital capacity and total lung capacity with preservation of FEV1. Breathing is shallow and rapid. The ventilation-perfusion ration is grossly reduced and this results in hypoxemia. These subjects are prone to develop repeated respiratory infections. In severe cases, respiratory failure may develop. Kyphoscoliosis may lead to chronic Cor Pulmonale. Management consists of early surgical correction in suitable cases, respiratory physiotherapy to improve ventilation, and prevention of respiratory infection.
Ankylosing spondylitis: In this condition, there is marked flexion and rigidity of the thoracic spine. Ventilation is carried out mainly by diaphragmatic movement. Though the vital capacity is reduced, signs of frank respiratory embarrassment are few.
Pectus excavation (Funnel chest, Pectus recurvatum): In this condition, there is a sharp posterior displacement of the body of the sternum from above downwards. A furrow develops in front of the chest, which is deepest just above the Xiphoid process. Pectus excavatum is usually congenital. Though present at birth, the deformity progresses to become more conspicuous as the body fat disappears. The deformity may aggravate during adolescence. The heart is rotated and displaced to the left. This may give rise to systolic murmurs, particularly along the left sternal border. Impairment of Cardiac function is rare.
Pectus Carinatum (Pigeon Chest): In this deformity, which is a sequel to childhood rickets in most cases, the sternum protrudes forwards with the ribs sloping steeply on either side. There is increased incidence of respiratory infections in these subjects. No specific therapy is indicated.
Injuries to the thoracic cage: The thoracic cage is often the seat of Injury in violent accidents. Fractures of individual ribs, contusion of the chest wall, contusion of the lungs, open wounds which lead to Pneumothorax, bleeding into the Pleura giving rise to hemothorax and surgical emphysema are all common. In comatose subjects injury to the chest wall and thoracic and abdominal viscera is likely to be missed. In many cases, these may prove fatal even if the neurological lesion is successfully tackled. The need for careful examination to exclude thoracic and abdominal injuries in cases of violent accidents cannot be overemphasized.
Flail Chest: When several ribs are fractured at multiple sites so that a portion of the Chest wall moves independently, the negative intrathoracic pressure during inspiration causes the fractured ribs to be sucked in, thereby preventing expansion of the lung. During expiration, this segment moves towards. When the injury is unilateral, air from the Lung of the affected side passes into the opposite healthy lung during inspiration and air is sucked into it from the normal lung during expiration. This type of paradoxical respiration is called “Pendulum breathing”. This results in serious respiratory insufficiency and respiratory failure.
In flail chest injury, as a first aid the chest wall should be stabilized to avoid suffocation. This can be done by applying towel clips to the area of paradoxical movement and exerting traction during inspiration. The patient is transported to hospital. Stabilization can be maintained by weight traction. Internal fixation is done surgically in severe cases.