Examination of the thumb

Thumb motion	Patient	Examiner
Extension at MCP	Extend thumb fully.	Push on proximal phalanx, trying to flex thumb at MCP joint.
Extension at IP	Extend thumb fully.	Push on distal phalanx, trying to flex thumb at IP joint. Stabilize the proximal phalanx with other hand.
Flexion at MCP	Touch thumb to hypothenar eminence.	Grasp thumb distally and try to pull out of flexion.
Flexion at IP	Flex thumb at IP joint and hold position.	Try to pull distal phalanx into extension.
Palmar abduction	With thumb and fingers aligned, in the same plane, abduct thumb to position perpendicular to palm.	Push distally on thumb trying to return it to the plane of the palm.
Palmar adduction	From position of palmar abduction, move thumb to plane of palm.	Push distally on thumb resisting movement toward the plane of the palm.
Opposition	Touch thumb tip to tip of little finger and maintain "circle" shape. This method isolates OP muscle. Can also be tested using index finger, which involves both OP and first IO muscles.	Hook a finger into the circle and try to disrupt the "pinch."
Adduction	Align fingers and thumb parallel and in same plane, and hold this position.	Grasp thumb and attempt to pull it out of adduction to position in plane of palm but at a 45 degree angle with the axis of the palm and fingers.

IP: interphalangeal; MCP: metacarpophalangeal.

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