The most commonest site of bleeding in haemoptysis is
Ref Harrison 19 th ed/pg 1793 The most common source of bleeding in massive hemopthaemo are the bronchial aeries which are pa of the high pressure systemic circulation . In bronchitis, bronchiectasis or with endobronchial tumors. Ref Harrison 19th edition pg 1793
Tracheobronchial tree
Pulmonary parenchyma
Pleural disease
All the above
Respiratory system