Clubbing is a physical sign characterized by bulbous enlargement of the ends of one or more fingers or toes (Figure 44.1). Proliferation and edema of connective tissue result in loss of the normal angle between the skin and nail plate and excessive sponginess of the nail base. Clubbing is usually acquired and is associated with certain cardiopulmonary and gastrointestinal disorders, but may occur in congenital or familial forms. Acropachy is an alternative term for clubbing. Acquired clubbing is often reversible when the associated condition is treated successfully.