A 29-year-old industrial worker falls onto an outstretched h…

A 29-year-old industrial worker falls onto an outstretched hand after walking on a slippery floor in the loading dock. They present with hand pain and swelling. Also, they report immediate tenderness and difficulty making a fist. On examination, there is swelling and point tenderness over the dorsum of the hand, specifically at the neck of the fifth metacarpal. What is the most likely diagnosis?