symphalangia /sim′fəlan″jē·ə/ [Gk, syn, together, phalanx, finger] , 1. a condition, usually inherited, characterized by ankylosis of the fingers or toes. 2. a congenital anomaly in which webbing of the fingers or toes occurs in varying degrees, often in conjunction with other defects of the hands or feet. Also called symphalangism. See also syndactyly.