The Allen Arm Positioner provides a solution to positioning problems that can at times be encountered during the course of a surgical procedure on the shoulder. It is a lightweight device, weighing only 6 pounds, and is an excellent accessory to have in place during open or arthroscopic procedures such as clavicle fracture repair, rotator cuff repair, total shoulder arthroplasty, and elbow fracture repair. The Arm Positioner indexes at the elbow, thereby providing complete positioning control of the shoulder joint. While it solidly maintains a selected position, the device can also be positioned in a semi-locked state, enabling the surgeon to easily move the arm if needed without having to make a tension adjustment. The device is easy to steam clean and is the only autoclavable positioning device on the market.