synpolydactyly

Here is an example of syndactyly in which several fingers are fused into one large digit. The thumb and forefinger are fused in this case.

Polydactyly, particularly of all extremities, strongly suggests trisomy 13. Extra toes are seen here on each foot.

An extra finger (polydactyly) is present on this hand of an infant with trisomy 13.