All of them are fingers. Thumbs are fingers, but a finger is not necessarily a thumb. I dont know where people get the idea that a thumb is not a finger. So many common sayings reinforce that it is. “Counting on your fingers (including your thumbs)”, healthy babies have “Ten fingers, ten toes”, “What did the five fingers say to the face… slap”, “high five”, “five finger discount”, etc. Also, honorable mention to Princess Bride’s Inigo Montoya searching for “the 6 fingered man” which includes his thumb. “Middle finger” is not the only thing that makes no sense if you don’t accept that the thumb is a finger.