A simple test on your wrist can reveal a fascinating link to human evolution through the palmaris longus tendon.

This tendon, once vital for tree-dwelling primates to swing between branches, is now vestigial. As humans no longer rely on it, about 10-15% of people have evolved without it. To check if you have it, place your forearm on a table, palm up, and touch your pinky to your thumb while lifting your hand slightly. A visible raised band in the wrist means you still carry this evolutionary relic.

If not, you’re part of the evolutionary shift! Either way, this simple test highlights our shared history with primates and the ongoing journey of human evolution.