Which ligament forms a "roof" over the humeral head?

The coracoacromial ligament plays a crucial role in stabilizing the shoulder by forming a "roof" over the humeral head. This ligament extends from the coracoid process of the scapula to the acromion, thereby creating a protective arch that helps prevent superior displacement of the humeral head during arm movements. This structural feature is important for maintaining the integrity of the shoulder joint, allowing for a greater range of motion while preventing injuries such as shoulder impingement. The setup of the coracoacromial ligament enhances the stability of the shoulder, making it essential for activities that involve lifting and overhead motions.