Thumbs are the short, thick digits located on the side of each hand. They are opposable, meaning they can move to touch the other fingers, which allows for a strong grip and precise manipulation of objects. This unique feature is crucial for tasks like holding tools, writing, and performing everyday activities. The structure of a thumb includes two bones called phalanges, along with muscles and tendons that enable movement. The human hand typically has a thumb on each side, contributing to the overall dexterity and functionality of the hand in various tasks, from typing to playing musical instruments.