Histologic comparison of the costochondral, sternoclavicular, and temporomandibular joints during growth in Macaca mulatta.

The costochondral joint (CCJ) is commonly used to replace defective mandibular condyles in children for the restoration of normal temporomandibular (TMJ) growth and function. However, continued and harmonious growth following rib grafting is the exception rather than the rule. This may be due to the differences in the growth characteristics of the costal cartilage and the condyle. A joint that is similar both developmentally and structurally to the TMJ is the sternoclavicular joint (SCJ). The purpose f this study was to describe histologically the SCJ and CCJ during growth in Macaca mulatta and to compare the histomorphologic features with those of the TMJ. Costochondral and sternoclavicular joints were obtained from infant, juvenile, adolescent, and adult Macaca mulatta. The histologic sections were compared with mandibular condyles of the same ages available in our laboratory. The results indicate that the TMJ and SCJ are very similar morphologically throughout the growth period. The clavicular head contained layers of cartilage typical of the mandibular condyle, i.e., articular, prechondroblastic, chondroblastic, hypertrophic, and endochondral ossification layers, at each age during growth. Like those in the condyle, the hypertrophic cartilage cells were arranged in an apparently random, noncolumnar fashion. The CCJ, however, did not resemble the condyle but appeared to be more similar to the growth plate in a long bone epiphysis during growth. The results of this investigation indicate that the SCJ may be more suitable for mandibular condylar replacement than the CCJ.