ligaments of the thumb
ligaments of the thumb

Testing the Collateral Ligaments of the Thumb

By Ben Benjamin, PhD
February 1, 2019

Testing the Collateral Ligaments of the Thumb

By Ben Benjamin, PhD
February 1, 2019

Passive Valgus of the MP Joint

Remember that the ulnar collateral ligament of the metacarpophalangeal (MP) joint is located right at the edge of the web of the thumb; it holds the medial side of the joint together so that it doesn't side-flex more than a tiny bit. The test for this structure is passive valgus of the MP joint. Place your thumb on the lateral aspect of the MP joint and your index finger on the medial aspect of the interphalangeal (IP) joint. Now press medially with your thumb and laterally with your index finger. If this is painful at the medial side of the joint, the person has strained the ulnar collateral ligament of the MP joint.

Passive Varus of the MP Joint

The radial collateral ligament is opposite the ulnar collateral ligament, on the lateral side of the MP joint. To test this structure, place your index finger at the lateral side of the IP joint and your thumbs on the medial aspect of the MP joint at the edge of the web of the thumb. Now exert a varus stress by pressing the thumbs laterally and the index finger medially. If this test hurts at the lateral aspect of the MP joint, the radial collateral ligament of the MP joint is injured.

Passive Valgus of the IP Joint

To place valgus stress on the ulnar collateral ligament at the IP joint, place your index finger on the lateral aspect of the IP joint and your thumb pad on the medial aspect of the tip of your thumb. Now press laterally with your thumb and medially with your index finger. If this is painful, the ulnar collateral ligament of the IP joint is injured.

Passive Varus of the IP Joint

To place varus stress on the radial collateral ligament at the IP joint, place the side of your thumb pad on the medial aspect of the IP joint and your index finger pad on the lateral tip of the client's thumb. Now press laterally with your thumb and medially with your index finger. If this is painful, the radial collateral ligament of the IP joint is injured.