The pronator teres

Pronator teres · musculus pronator teres

A forearm muscle that turns your palm face down.

What it does

The pronator teres runs diagonally from the inner side of the elbow to the middle of the radius. It rotates the forearm to turn the palm down, as when you pour from a jug, and helps bend the elbow.

Surprising fact

The median nerve usually passes between its two heads, and a tight muscle here can squeeze the nerve and cause tingling in the hand that mimics carpal tunnel syndrome.