There is cavity in the hand called the Anatomical Snuff Box

Anatomical terms have a tendency to be long, difficult to pronounce and easy to forget. Posterior, anterior, radial, metacarpal, abductor pollicis longus, dorsal cutaneous. However, some terms are reasonable. The hand, for example, has an "anatomical snuff box."

This section is triangular deepening on the outer thumb-side of the hand. Technically, it is at the radial, dorsal aspect of the hand at the carpal bone level. It gets it's name from the practice of sniffing powdered tobacco or "snuff" off of this area.

The snuff box is formed by two tendons, and hence is more pronounced when the thumb is extended.

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