Syndactyly refers to fusion of fingers or toes. It is amongst the most common congenital anomalies. Syndactyly can occur as a sole anomaly. In other cases, it may be associated with ring constrictions, polydactyly, craniofacial deformities, and cleft hands. Reference: https://emedicine.medscape.com/article/1244420-overview#a1 Image via: https://www.orthobullets.com/hand/6076/syndactyly