In human

Human

Humans are the only living species in the Homo genus...

 anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

, the clavicle or collar bone is a long bone

Long bone

The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow...

 of short length that serves as a strut between the scapula

Scapula

In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....

 and the sternum. It is the only long bone in body that lies horizontally. It makes up part of the shoulder

Shoulder

The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

 and the pectoral girdle and is palpable in all people, and, in people who have less fat in this region, the location of the bone is clearly visible as it creates a bulge in the skin.

It receives its name from the ("little key") because the bone rotates along its axis like a key when the shoulder is abducted

Abduction (kinesiology)

Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

, and it roughly the same shape as Roman door lock keys.

The clavicle is a doubly curved short bone that connects the arm (upper limb

Upper limb

The upper limb or upper extremity is the region in an animal extending from the deltoid region to the hand, including the arm, axilla and shoulder.-Definition:...

) to the body (trunk

Torso

Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen.-Major organs:...

), located directly above the first rib.