Where should ultrasound be applied for the peroneus longus and brevis tendons?

• A. Posterior to lateral malleolus
• B. Directly over Achilles tendon
• C. Anterior to lateral malleolus
• D. Over medial malleolus

Answer: (A)

The peroneal tendons sit along the outer ankle and pass behind the lateral malleolus in the retromalleolar groove, so the best ultrasound window to visualize both the peroneus longus and brevis is directly behind the lateral malleolus. Placing the probe there lets you see how the tendons course behind the bone and along the outer aspect of the foot, which is essential for assessing tears or tenosynovitis. Imaging directly over the Achilles tendon targets a different structure, while positioning anterior to the lateral malleolus would view the front tendons, not the peroneals, and placing over the medial malleolus would show tendons like tibialis posterior and flexor tendons.