Fuckles

The metatarsophalangeal joint between the metatarsals and the phalanges.

The knuckles on your feet.

Foot knuckles.

Fuckles.

1. Some ballerinas are warming up, and there is a snapping sound. "What was that?" "I just cracked my fuckles."

2. "I broke my fuckles when I was piss drunk and decided to fight a cinder-block."