Thumb FAQs:

Q: Is thumb the first digit of the hand?

A: Yes.

Q: Is thumb the stoutest of the fingers?

A: Yes.

Q: Is thumb extended in a "thumbs-up"?

A: Yes, It has been suggested that the variation is an autosomal recessive trait, called a "Hitchhiker's thumb", with homozygous carriers having an angle close to 90°. However this has been disputed, as the variation in thumb angle is continuous and shows little evidence of the bi-modality seen in recessive traits.

Q: Is thumb divided into a proximal and a distal compartment?

A: Yes, and the former more deformable than the latter, which allows the thumb pad to mold around an object.

Q: Is thumb placed squarely in contact with - or diametrically opposite to - the terminal pads of one or all of the remaining digits?

A: Yes.

Q: Are thumbs a signature feature of the primate family?

A: Yes, and played a large role in the ancient humans' invention and use of tools.

Q: Is thumb not opposable in all primates — some primates?

A: Yes, and such as the spider monkey and colobus, are virtually thumbless.

Q: Is thumb usually associated with Homo habilis?

A: Yes, and a forerunner of Homo sapiens.

Q: Is thumb the outermost digit?

A: Yes.

Q: Are thumbs shared by some primates?

A: Yes, and including most catarrhines.

Q: Is thumb approximated to the fifth digit and refer to other approximations between the thumb and other digits as apposition?

A: Yes.

Q: Is thumb capable of bending in such a way that it can touch all the other digits on the hand or foot?

A: Yes.

Q: Is thumb pollex?

A: Yes, and the corresponding adjective for thumb is pollical.