What is the flap of skin on your elbow called?

The flap of skin covering the region of the elbow is the olecranal skin. It covers the olecranon, which is the medical term for the bone comprising the elbow.

The olecranal bursa lies on top of the olecranon and beneath the olecranal skin. This liquid sac reduces friction and protects against external stresses to the elbow that can result in injury. Without medical attention, inflammation of the olecranal bursa itself results in bursitis and possible injury to the elbow bone. Causes of inflammation are infection, arthritis, blunt-force injuries and excessive pressure for prolonged periods of time. Solutions to olecranal bursitis are medical procedures or cushioned support.