There are eight muscles and four tendons that pull and move our thumbs in different directions, helping us with tasks throughout the day. These tendons are subject to many stresses and inflammation, collectively known as tendonitis.
Maybe it was the ice, a loose stair tread, wet leaves or an uneven sidewalk. Whatever the reason, a FOOSH (fall on out-stretched hand) is a very typical way to break your wrist or a finger.