[Ontogeny of the human temporomandibular joint]

An analysis of the human temporomandibular joint is done regarding to the appearance of secondary cartilage formations during the prenatal development of condylus and temporal joint elements. Sagittal sections of nine human fetuses (49 mm CRL to 315 mm CRL) show a closed relationship between the development of the bony and soft tissues of the joint. The temporary appearance of secondary cartilage in the temporal joint area is induced by the functional loading of the capitulum. This process requires the genesis of the two free articular cavities on the one side and the functional attachment of the lateral pterygoid muscle to the discus and the collum mandibulae on the other. Pointing out the clear relationship of the articulating joint surfaces and the in between discuss, a left temporomandibular joint of a fetus (125 mm CRL) is reconstructed in a medioventral view with the help of a three dimensional drawing. The location of the temporal secondary cartilage formation within the centre of the temporal loading area of the condyle assures its functional genesis during the embryological development of the human temporomandibular joint.