Question

Which structure passes deep to the flexor retinaculum at the ankle?

• A. Posterior tibial artery
• B. Long (great) saphenous vein
• C. Tibialis anterior tendon
• D. Peroneus tertius

Hint:

Think tarsal tunnel - Tom, Dick, And Very Nervous Harry.

Answer 1

The Correct Option is A

Step 1: The flexor retinaculum on the medial side of the ankle converts a groove behind the medial malleolus into the tarsal tunnel, and several structures pass deep to it.

Step 2: The contents passing deep to the flexor retinaculum, from front to back, can be recalled as Tom, Dick, And Very Nervous Harry: Tibialis posterior tendon, flexor Digitorum longus tendon, posterior tibial Artery, posterior tibial Vein, tibial Nerve, and flexor Hallucis longus tendon. So the posterior tibial artery is among them.

Step 3: The other options run elsewhere: the long saphenous vein lies subcutaneously in front of the medial malleolus, while tibialis anterior and peroneus tertius are anterior compartment tendons that pass under the extensor retinaculum.

Step 4: Hence the posterior tibial artery is the correct answer.