What is the primary function of the clavicle in the human body?

The primary function of the clavicle, commonly known as the collarbone, is to connect the arm to the body. It acts as a vital support structure that links the upper limb to the trunk, providing stability for shoulder movement. This connection is essential for a wide range of arm and shoulder activities, allowing for a full range of motion and playing a crucial role in the mechanics of the shoulder girdle.

The other functions, while important in their own right, do not directly pertain to the clavicle. The clavicle does not support the head; that function is carried out by the vertebral column and associated neck muscles. It also does not provide any protection for the rib cage, as that is primarily the role of the ribs themselves, which encapsulate and safeguard the thoracic organs. Lastly, stabilization of the knee is unrelated to the clavicle; knee stabilization involves structures like ligaments, tendons, and muscles around the knee joint. Thus, in the context of its anatomical role, connecting the arm to the body is the most accurate description of the clavicle's primary function.