Which test is used to confirm suspected Achilles tendon rupture by squeezing the calf?

• A. Lachman test
• B. Phalen test
• C. Tinels test
• D. Thompson test

Answer: (D)

Testing Achilles tendon integrity by squeezing the calf checks whether the gastrocnemius-soleus complex can transmit force to the ankle to produce plantarflexion. When you squeeze the calf, a normal, intact Achilles tendon should cause the foot to plantarflex. If the tendon is ruptured, the force from the calf squeeze cannot be transmitted to the foot, so plantarflexion is absent or markedly diminished. This is why the Thompson test is the chosen method to confirm an suspected Achilles tendon rupture.

In practice, the patient is typically lying face down with the knee extended. A normal response shows the foot plantarflexing with calf squeeze. A positive finding—no plantarflexion—strongly suggests rupture. Partial ruptures may still allow some plantarflexion, so the test is most definitive for complete tears.

The other tests target different structures: for example, Lachman tests anterior knee translation to assess ACL integrity, while Phalen and Tinels tests evaluate nerve compression in the wrist. They don’t evaluate the Achilles tendon, so they aren’t relevant for confirming an Achilles rupture.