Thumb Articulations

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Carpometacarpal Flexion Bending the joint resulting in a decrease of angle; moving the bone below the thumb toward the hand and slightly Forward. Flexor pollicis brevis Flexor pollicis longus Opponens pollicis   Extension Straightening the joint resulting in an increase of angle; moving the bone below the thumb away from the hand and slightly back. Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus   Adduction Medial movement toward the midline of the body; moving the bone below the thumb toward the back of the wrist. Adductor pollicis 1st dorsal interosseous Extensor pollicis longus Flexor pollicis longus   Abduction Lateral movement away from the midline of the body; moving the bone below the thumb toward the front of the wrist. Abductor pollicis longus Abductor pollicis brevis   Opposition Diagonal movement of the thumb across the palm of the hand making contact with the fingers. Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis Flexor pollicis longus Adductor pollicis   Metacarpophalangeal Flexion Bending the joint resulting in a decrease of angle; moving the base of the thumb toward the heel of the hand. Flexor pollicis longus Flexor pollicis brevis 1st palmar interosseous Abductor pollicis brevis   Extension Straightening the joint resulting in an increase of angle; moving the base of the thumb away from the heel of the hand. Extensor pollicis longus Extensor pollicis brevis   Adduction Medial movement toward the midline of the body; slight movement of the base of the thumb toward the back of the hand. Adductor pollicis 1st palmar interosseous   Abduction Lateral movement away from the midline of the body; slight movement of the base of the thumb away from the back of the hand. Abductor pollicis brevis   Interphalangeal   Flexion Bending the joint resulting in a decrease of angle; moving the distal segments of the thumb toward the base of the thumb. Flexor pollicis longus   Extension / Hyperextension Straightening the joint resulting in an increase of angle; moving the distal segments of the thumb away from the base of the thumb. Extensor pollicis longus Abductor pollicis brevis Adductor pollicis   Notes See Wrist for midcarpal joints. Also see Fingers.