My fair lady. If you're familiar with the lyrics, you can likely venture a guess as to the nursery rhyme's meaning: London Bridge is falling down, falling down, falling down! This sing-along song is based on one of the most well-known landmarks in London -- a bridge that once spanned the River Thames.
These tendons can become pinched in the ankle joint at times. You could have some synovitis inside the ankle joint, which is being pinched within the joint. Sometimes, loose bodies or talar dome lesions can cause sharp pain inside of the ankle joint.
The foot and ankle is a remarkably complex part of the body with many intricate parts. As such, problems with any of a number of things can cause the pain. Bones, muscles, tendons, ligaments, and nerves are all the possible culprit. Common causes include inflammation of the ankle tendon. This can be caused by overuse, and does result in sharp pain with motion as you suggest.