Your upper eyelid is attached to a muscle that allows it to move up and down to cover or reveal your eye. This is aided by a smaller, supporting muscle. A muscle behind the skin of your brow also helps to elevate your eyelids from above. These are all part of the complex system of muscles that control your face. The simple muscle of your upper eyelid is called the levator palpebrae superioris (LPS). It's a small muscle located just below the skin of your upper eyelid. It works with the larger LPS to lift your eyelid when you open your eyes. The LPS runs along the side of your head, beneath your ear, and ends in your eyebrow. If you look in a mirror and raise an eyebrow, you'll see how this small muscle lifts your eyelid. It does so by pulling on hair that has grown out from inside your skull, above your ear. This creates a tension within the muscle that causes it to contract. As it contracts, it pulls your eyelid up and back, covering your eye. People don't often think about their eyelid muscles, but they do exist! They help us blink, watch television with our eyes closed, and even smile. The LPS is especially important because without it people would be unable to hide their emotions. The LPS is used in facial expressions such as crying and frowning.