Which of the following describes the actions of the infraspinatus muscle?

The infraspinatus muscle plays a crucial role in shoulder movements and is primarily responsible for the lateral rotation of the humerus. It is one of the rotator cuff muscles, situated on the posterior aspect of the scapula. This positioning allows it to effectively aid in rotating the humerus away from the body, which is known as lateral rotation.

Furthermore, the muscle contributes to the stability of the shoulder joint by providing dynamic support, particularly during arm movements. Additionally, it assists in extending the arm when the shoulder is in a position that allows this movement. Hence, its functions align well with lateral rotation and extension of the humerus.

Understanding the actions of the infraspinatus helps clarify its role in shoulder mechanics, particularly in activities requiring shoulder stabilization and rotation, such as throwing or lifting movements. This anatomical knowledge is essential for professionals working in orthotics and prosthetics, as it informs the design and application of devices that may interact with the musculature and biomechanics of the shoulder.