Kristen Gasnick, PT, DPT, is a medical writer and a physical therapist at Holy Name Medical Center in New Jersey.

Isaac O. Opole, MD, PhD, is a board-certified internist and a current teaching professor of medicine at the University of Kansas.

The clavicle, also referred to as the collar bone, is an elongated, S-shaped bone that sits between the shoulder and sternum at the top of the ribcage. It provides structural support between the shoulder and the rest of the skeleton, and is one of the most frequently fractured bones in the body.

The clavicle joins the scapula, or shoulder blade, and sternum to form two joints on either end of the bone, which are:

The relative size of the clavicle leaves it particularly susceptible to fracture. Fracture of the clavicle can occur from a fall landing on an outstretched hand or through a direct blow to the shoulder. The middle third of the clavicle is most commonly fractured, accounting for about 80% of all cases of clavicle fractures.

The clavicle and scapula together are collectively referred to as the pectoral girdle, or shoulder girdle.

The clavicle connects the shoulder to the rest of the skeleton. Its positioning allows for increased range of motion of the shoulder away from the body and helps protect the arm by dispersing force transmitted through direct contact.

The clavicle has a small degree of movement in elevation and depression (upward and downward movement), protraction and retraction (forward and backward movement), and rotation.

The subclavius, which means “beneath the clavicle,” is the primary muscle that controls the clavicle. It originates at the first rib, and attaches to the underside of the clavicle. When contracted, the subclavius, controlled by the subclavian nerve, causes the clavicle to depress, or move downwards.

The anterior deltoid, trapezius, sternocleidomastoid, and pectoralis major muscles all attach to the clavicle for support, and cause a small degree of multidirectional movement as well.

The midclavicular line, a vertical line drawn down the body from the midpoint of the clavicle, serves as an important anatomical landmark for locating other structures, including the apex of the heart, where a stethoscope can be placed to listen to the heartbeat.

The clavicle and associated joints can become damaged from injury or repetitive overuse of the shoulder. Common conditions associated with the clavicle include the following.

Trauma to the acromioclavicular joint, such as a direct blow to the front of the shoulder or falling and landing on an outstretched hand, can injure the ligaments holding the acromion and clavicle together. This can result in either an acromioclavicular joint sprain or separation of the joint. Symptoms include pain localized specifically at the acromioclavicular joint at the top of the shoulder.

Injury to the shoulder, especially direct trauma to the front of the shoulder, can cause the clavicle to fracture. Symptoms include pain at the clavicle and shoulder, as well as pain and difficulty with moving the arm.

The sternoclavicular joint, between the clavicle and sternum, can become dislocated with injury to the front of the shoulder, causing pain and swelling around the injured area. 

The end of the clavicle, or distal portion, that forms the acromioclavicular joint can become irritated and inflamed. Osteolysis, or bone degeneration, can easily occur at the end of the clavicle due to the high degree of stress and repetitive forces placed through the small surface area of the acromioclavicular joint, especially with heavy lifting such as bench press or military press. The bone begins to break down at a faster rate than it is able to heal and form new bone cells. Sharp pain commonly occurs with overhead and pushing movements of the arm and shoulder with a dull ache at rest. 

Aging and repetitive overuse of the shoulder can lead to degeneration of the cartilage and the development of arthritis within the acromioclavicular joint, causing inflammation within the shoulder and pain with arm movements.

Depending on the extent of your condition, rehabilitation for conditions associated with the clavicle or associated joints include the following:

The clavicle is considered a long bone, since it's longer than it is wide. Long bones have two main parts. The diaphysis is the central part of the bone and the epiphysis is the rounded end of the bone.

A broken collarbone can take several months to heal. If you have diabetes or smoke, it may take longer. Most of the time, you can return to normal activities within three months.

Hansen, JT. Chapter 7; Upper Limb. In Hansen JT, ed. Netter’s Clinical Anatomy 3rd ed. Saunders/Elsevier; 2014:347-352.

American Academy of Orthopedic Surgeons. OrthoInfo. Clavicle Fracture (Broken Collarbone).

Harvard Medical School. Harvard Health Publishing. Shoulder Sprain.

Hospital for Special Surgery. Osteolysis.

American Academy of Orthopaedic Surgeons. Clavicle fracture (broken collarbone).

By Kristen Gasnick, PT, DPT Kristen Gasnick, PT, DPT, is a medical writer and a physical therapist at Holy Name Medical Center in New Jersey.

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