Unless you are particularly dim, the diagnosis should be pretty obvious, right?
Polydactyly.
How is polydactyly classified?
According to the location of the extra digit. Pre-axial: the extra digit is on the thumb / big toe side. Post-axial: the extra digit is on the little finger / toe side.
Which is more common, pre or post axial?
Post axial is over twice as common (1:3000 vs 1:7000).
Can you name some syndromes associated with polydactyly?
It is ok if you can't, but there are many. Trisomy 13; Bardet-Biedl syndrome; Carpenter syndrome; fetal valproate syndrome hydrolethalus syndrome; Joubert syndrome; Juberg-Hayward syndrome; Lhermitte duclos disease; Meckel Gruber syndrome; McKusick-Kaufman syndrome; Megalencephaly, polymicrogyria, polydactyly, and hydrocephalus (MPPH) syndrome; oral-facial-digital syndromes; Pallister-Hall syndrome; Short rib polydactyly syndrome etc…(you get the picture).