1 definition by Mungo260

Top Definition
When someone (usually of the tall variety) stands up straight and their knees look like a fetus face. Also knows as 'Old Man Face Knees'.
Me: Hey Stratho, look at the tall chick. She has fetus knees. Weird.

Stratho: I like it.
by Mungo260 January 08, 2016

Mug icon
Buy a Fetus Knees mug!