Clavicle AnatomyCredit:

The word clavicle is derived from the Latin word “clavis”, meaning key. It is an S-shaped bone that connects the trunk with the upper extremities. It is known in layman’s terms as the collar bone. It is the first bone to ossify, and is the most fractured long bone in the body. The clavicle serves as the connection of the arm to the trunk, and functions to provide support for the upper limb and shoulder. In turn, the clavicle also enables the transmission of upper extremities to the trunk.



Anatomy of the clavicleCredit:

The clavicle is the first bone to ossify, occurring at around the 5th-6th week of gestation.  Another unique feature of the clavicle is that it is the only long bone with two centers of ossification. Further, it is the only long bone that undergoes membranous ossification.


Parts of the clavicle

Collar bone AnatomyCredit:

The anatomy of the clavicle is comprised of three main parts: two ends, a medial end or the sternal end and a lateral end or acromial end. These ends are connected by a cylindrical area called the shaft.  The shaft of the clavicle is curved slightly, and a s such can be divided into the medial two thirds where it is convex, and a lateral third where it is concave. The lateral end and the medial end can be differentiated by its structure and shape.

1) The lateral end is smaller and flat

2) The the medial end is larger and quadrangular in shape.

 These ends give origin to important muscles. For example, the anterior surface of the medial end is the origin of the pectoralis major, the chest muscles.



Anatomy collar boneCredit:

The clavicle is found in between the sternum and the scapula. It is the only bone which serves as a direct connection between the trunk and upper extremities. It overlies important nerves and blood vessels.  The lateral end articulates with the acromion process of the scapula. This forms the acromioclavicular joint. The medial end articulates with the sternum through a clavicular notch. This forms the sternoclavicular joint. Aside from this, the medial end of the clavicle also articulates with the first costal cartilage.


Important Structures

Anatomy of the Collar boneCredit:

Clavicle anatomy is important to know because it overlies very important nerves and blood vessels. Underneath the medial third of the clavicle passes the subclavian vessels as well as the trunks of the brachial plexus, going to the arm. Although the clavicle is frequently fractured, it is rare that these are affected. In addition, behind the sternoclavicular joint, the common carotid artery and the brachiocephalic artery can be found. Lateral to this one can find the internal jugular vein.


Fractured Clavicle

Anatomy ClavicleCredit:

The clavicle is one of the most commonly fractured bones of the body. This is usually due to falling on the shoulder or hand, wherein the force transmitted to the axial skeleton is too great. The fracture usually occurs at the junction of the medial two-third and lateral one-third, which is the weakest and most vulnerable part of the bone.



The clavicle is a unique and important bone. The clavicle is an S shaped bone which has a lateral end, a medial end and a shaft. The lateral end articulates with the acromion to form the acromioclavicular joint, while the medial end articulates with the sternum at the sternoclavicular joint. The medial end is also attached to the first costal cartilage. It is the only direct connection between the trunk and the upper limb. It is also an important bone because it is a common site of fracture.  It is an important site of muscle attachment. Knowing the anatomy of the clavicle is very helpful in understanding how the upper limbs and trunk work.