A 35-year-old sprinter feels a sudden snap in his calf while running. He cannot push off the affected foot. On prone examination with the feet hanging over the edge of the table, squeezing the right calf produces no plantar flexion of the foot. This positive test confirms rupture of the:

• A Achilles tendon ✓
• B Gastrocnemius muscle belly
• C Plantaris muscle
• D Tibialis posterior tendon

Explanation

The Thompson (Simmonds) test is diagnostic for Achilles tendon rupture: calf squeeze in the prone position should produce passive plantar flexion through an intact tendon. Absence of plantar flexion confirms complete rupture. Plantaris rupture and gastrocnemius tear (tennis leg) preserve the continuity of the Achilles tendon, so plantar flexion still occurs. Tibialis posterior is an invertor and does not drive plantar flexion on calf squeeze.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.