The sternoclavicular joint (SJ) is one of the sites for articulation in the human body. It is located at the junction of the sternum and clavicle. With this joint, the shoulder is able to extend its range of motion, thus enabling us to do different activities of daily living such as lifting, playing, dancing, and many others. The joint of sternoclavicular is very important and it is worth of studying.
Overview of the Sternoclavicular Joint
The sternoclavicular joint is situated at the proximal end of the collar bone (clavicle) and the manubrium’s superior clavicular notch. The joint is a saddle-type that gives the clavicle its capability to move within the horizontal and vertical plane. The joint of sternoclavicular has a big role in motioning the arm and shoulder backward and forward. This joint is stabilized by the following structures:
- Credit: http://wn.com/sternoclavicular_jointPosterior sternoclavicular ligament – covers the back surface of the sternoclavicular joint
- Anterior sternoclavicular ligament – covers the front surface of the sternoclavicular joint
- Credit: http://bjsm.bmj.com/content/44/5/361.abstractInterclavicular ligament – located between both the two clavicles, passing over the sternum
- Costoclavicular ligament – the shortest ligament attached to the SC joint; connects the clavicle with the first rib
- Credit: http://www.pt.ntu.edu.tw/hmchai/Kinesiology/KINupper/Shoulder.htmarticular disc – the thickest and most fibrous ligament of the SC joint; connects the clavicle with the first rib and support certain motion of the shoulder
- Articular capsule – surrounds the SC joint; keeps the proximal end of the clavicle from pointing up.
General Characteristics of the Sternoclavicular JointCredit: http://www.drdavidgeier.com/injuries/sternoclavicular-dislocations/
Almost all joints allow movements in certain degrees while others do not allow any movement. The sternoclavicular joint enables the clavicle and shoulder to move in a great extent. There are two layers of a SC joint; the outer and inner layer. The outer layer, also known as the stratum fibrosum, is composed of avascular white fibrous tissue. The outer layer is abundant with nerve endings and nerve roots. The inner layer, also known as the stratum synoviale, is made up of fluid. It is crucial in reducing friction between the two joining bones. Because of the synovial fluid, the clavicle could slide smoothly and painlessly over the manubrium.
Injuries Pertaining to the Sc JointCredit: http://www.orthogate.org/patient-education/shoulder/sternoclavicular-joint-problems.html
Every joint in our body is susceptible to injuries and disorders. The SC joint is no exception. The injuries usually occur when one or more ligaments are disrupted and the clavicle is dislocated. Significant external force could move the clavicle out from its normal position. The most common type of SC dislocation is the anterior dislocation. The external force is not necessarily applied directly at the clavicle but it could be from the shoulder, forcibly rotating it backwards and sending stress on the SC joint.
Summary of the Sc Joint
The sternoclavicular joint is truly an amazing structure of our body. It allows us to move our shoulder backward and forward. It is supported by different ligaments and protected by an outer layer. The inner layer secretes synovial fluid that allows smooth movement.
If we are not careful, the SC joint may sustain debilitating injuries. This article has helped you to better understand the sternoclavicular joint and how it works.