This video demonstrates how to examine for clubbing of the fingers, as seen in various cardiac, respiratory and gastrointestinal illnesses.
The causes for clubbing are:
Cardiovascular Congential cyanotic heart disease, Subacute bacterial endocarditis, Atrial myxoma
Respiratory Lung cancer (mainly non small cell carcinoma), Interstitial lung disease, Suppurative lung diseases, Lung abscess, Bronchiectasis, Empyema, Cystic fibrosis, TB, Asbestosis with or without Mesothelioma, Arteriovenous malformations in the lung
Gastrointestinal: (All the 'C's) Cirrhosis, Coeliac disease, Crohn's disease, Colitis