Tearing of muscular fibre, which usually also damages blood vessels in the muscle because muscles have large numbers of blood vessels which provide oxygen and remove waste products. Tearing a muscle thus also causes haemorrhage, known as haematoma. Other symptoms are pain, particularly when using the damaged muscle, and resultant restricted movement. As muscular fibre on both sides of the damaged area contracts, an indentation may be felt at the point of the tear. Muscles can also be torn by injury from the outside, which may also damage other tissue. This is particularly common in sports such as wrestling. Sudden convulsive muscular contraction can also cause tearing; damage of this kind occurs in badly-trained muscle and those affected by muscular conditions. Pulmonary heart disease (cor pulmonare) Failure of the right-hand side of the heart caused by lung abnormalities; any lung condition associated with narrowing of the pulmonary blood vessels can eventually cause pulmonary heart disease because the right ventricle has to work harder to pump enough blood to the lung, and increasing constriction of the blood vessels finally overloads the ventricle (causing heart failure). Lung disorders that can cause pulmonary heart disease include emphysema, pneumoconiosis and any lung condition involving the abnormal accumulation of tissue. Embolisms in the arteries of the lungs can also impede circulation. No discomfort is caused until the right ventricle is overloaded, but as soon as it is, blood cannot be pumped to the lungs quickly enough, causing oedema in the legs, palpitations and finally cyanosis. Treatment is directed at the lung condition as well as the heart itself (such as improvement of its function with digitalis and diuretics).