Snapping Sternoclavicular Joint

Snapping sternoclavicular joint (SCJ) is a rare presentation in the SCJ. We present a case report detailing the presentation and treatment of unilateral snapping SCJ in a 14-year-old male patient. Clinical findings included the subluxation of the medial end of the clavicle in the anterior-posterior direction following a specific maneuver by the patient that involved repetitive external rotation with the arm in horizontal abduction. Dynamic ultrasound demonstrated an asymmetric widening of the right sternoclavicular joint in the neutral position with a pronounced subluxation in provocative positioning. At 3.5-year follow-up, he continued to remain pain-free without static deformity of the SCJ. Snapping SCJ is a benign phenomenon that does not require any intervention and is not associated with ligament laxity.

Is the spinal motion segment a diarthrodial polyaxial joint: what a nice nucleus like you doing in a joint like this?

This review challenges an earlier view that the intervertebral joint could not be classified as a diarthrodial joint and should remain as an amphiarthrosis. However, a careful analysis of the relevant literature and in light of more recent studies, it is clear that while some differences exist between the spinal articulation and the generic synovial joint, there are clear structural, functional and developmental similarities between the joints that in sum outweigh the differences. Further, since the intervertebral motion segment displays movement in three dimensions and the whole spine itself provides integrated rotatory movements, it is proposed that it should be classified not as an amphiarthrose, "a slightly moveable joint" but as a complex polyaxial joint. Hopefully, reclassification will encourage further analysis of the structure and function of the two types of overlapping joints and provide common new insights into diseases that afflict the many joints of the human skeleton.