syndactylism

[ArthuraCig]

birth defect in which there is partial or total webbing connecting two or more fingers or toes

[ScottLer]

Syndactylism is a genetic condition characterized by the fusion or webbing of two or more fingers or toes. This may involve the skin and soft tissues only, or may also include fused bones. It is one of the most common types of congenital hand or foot deformities.