Review Question - QID 218982

The medial clavicular physis fuses between 20-25 years of age.

Traumatic injuries to the sternoclavicular joint (SCJ) in adolescent patients are more commonly physeal injuries than true SCJ dislocations. As the last physis to ossify (18-20 years) and fuse (20-25 years), the physis is the weakest portion of the SCJ and is more prone to injury than the sternoclavicular ligamentous complex itself. These medial clavicular injuries are more often misdiagnosed as SCJ dislocations, when in reality they are likely to be Salter Harris I or II physeal fractures.

Schmeling et al. assessed the development of the medial clavicle epiphysis using plain chest radiographs. They utilized the pre-existing classification system (stage 1: non-ossified epiphysis, stage 2: discernible ossification center, stage 3: partial fusion, stage 4: total fusion) and defined a fifth stage characterized by total disappearance of the physeal scar. They observed that the earliest onset of total physeal fusion (stage 4) occurred at age 20 years in women and 21 years in men, and the earliest age of complete disappearance of the physeal scar (stage 5) occurred at age 26 for both genders.

Schulz et al. evaluated the time frame for ossification of the medial clavicular epiphysis based on CT studies. Separated into the 5 stages of ossification as described by Schmeling et al., the group used CT scans to determine the age at which each Schmeling stage occurs, and further stratified their data between males and females. They determined that the earliest age of stage 4 (fully ossified, physeal scar visible) was age 21 for both males and females, and the earliest age of stage 5 (fully ossified, physeal scar no longer visible) was age 21 for females and age 22 for males.

Figure A is an AP of the chest demonstrating with a right-sided medial clavicular physeal injury presenting as SC joint asymmetry. Illustration A is another AP of the chest with the asterisk marking a left-sided physeal fracture of the medial clavicle with posterior displacement. Illustration B is a right anterior oblique view with the arrowhead depicting the same injury. Illustration C is an axial CT slice where the asterisk marks the manubrial articular surface, the solid arrow marks the unossified medial clavicular epiphysis, the arrowhead marks small metaphyseal fragments, and the dotted arrow marks the medial clavicular metaphysis. Illustration D is a depiction of the Schmeling stages 2 through 5.

Answers 1, 2, 3, & 5: the medial clavicular physis is the last physis to close in the upper extremity, between 20 and 25 years of age.