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anatomic snuffbox, anatomical snuffbox
A depression in the skin formed at the posterior base of the thumb when the thumb is extended from the hand. The lateral (outer) wall of the snuff box is formed from the tensed tendons of the abductor pollicis longus and extensor pollicis brevis; the medial wall is formed by the tensed tendon of the extensor pollicis longus; the proximal wall is formed by the styloid process of the radius, and the distal wall is formed by the base of the first metacarpal. Under the floor of the snuff box, the scaphoid and trapezium wrist bones can sometimes be felt, and the radial artery runs under the snuff box as it loops laterally around the thumb.See: illustration