Clavicle

The clavicle, commonly referred to as the collarbone, is a slender, S-shaped bone located in the upper thoracic region and plays a crucial role in the skeletal and muscular anatomy of the shoulder.

Pectoral girdle front diagram

Anatomy and Structure

Gerrish's Text-book of Anatomy (1902)

The clavicle is a bilateral bone, meaning that there are two clavicles in the human body, one on each side. It connects the sternum (breastbone) medially to the acromion, a part of the scapula (shoulder blade), laterally. This bone has three primary parts:

Clavicle fracture

• Medial end or sternal end: Articulates with the manubrium of the sternum at the sternoclavicular joint.
• Lateral end or acromial end: Connects with the acromion of the scapula at the acromioclavicular joint.
• Shaft: The elongated body of the clavicle, which has a gentle S-shape.

Function

The clavicle serves multiple vital functions in the human body:

• Support: It provides anterior support for the shoulder, maintaining its lateral position.
• Protection: It acts as a protective barrier for vital nerves and blood vessels that pass underneath it, including the brachial plexus and subclavian vessels.
• Muscular attachment: Several muscles, including the deltoid and the trapezius, attach to the clavicle, facilitating various arm movements.

Clinical Significance

Due to its subcutaneous location (just beneath the skin), the clavicle is vulnerable to injuries. Some key clinical considerations include:

• Fractures: Clavicle fractures are common, especially from falls onto an outstretched arm or direct impacts to the shoulder.
• Osteoarthritis: Wear and tear can lead to arthritis in the acromioclavicular or sternoclavicular joints.
• Congenital anomalies: Rarely, individuals might be born with clavicular anomalies like a missing or abnormally shaped clavicle.
• Thoracic outlet syndrome: Compression of the neurovascular structures beneath the clavicle can lead to this syndrome, causing pain and weakness in the arm.

Associated Structures

• Scapula: The shoulder blade with which the clavicle articulates laterally.
• Sternum: The central chest bone connected to the medial end of the clavicle.
• Acromioclavicular joint: The joint where the clavicle meets the shoulder blade.

See Also

• Bone fractures
• Shoulder anatomy
• Thoracic outlet syndrome