Thumb Abduction and Adduction

The thumb is set at an angle to the plane of the other four digits, so that thumb abduction brings it slightly palmar as it moves away from the middle finger.

Muscles: abductor pollicis longus and brevis.

The plane of abduction/adduction of the thumb is at an angle to the other digits, but thumb adduction returns the thumb to a position beside the second digit, and toward the third finger.

Muscles: adductor pollicis.