[The great apophyses: Functional strain and relevance].

BACKGROUND: The structure of apophyses and apophyseal growth plates is not substantially different from those of epiphyses and epiphyseal growth plates. In contrast to epiphyseal growth plates, apophyses and apophyseal growth plates do not contribute to the longitudinal growth of the extremity. They are associated with their adjacent joints, triggering the lengths of their lever arms and influencing their external shape and internal architecture. The formative stimulus on apophyses is given by muscles and tendons inserting at the apophysis or canopying the apophsis.

APOPHYSIS OF THE GREATER TROCHANTER: The apophysis of the greater trochanter significantly contributes to the lever arm length of the hip joint. Its growth activity triggers the neck-shaft angle and finally the centration of the hip joint.

TIBIAL APOPHYSIS: The tibial apophysis interacts with the slope of the proximal tibia and hereby influences the sagittal stability of the knee joint. A damage to the growth plate of the tibial tubercle leads to an anteverted tibial slope and a genu recurvatum difficult to treat.

CALCANEAL APOPHYSIS: The calcaneal apophysis determines the length and position of the calcaneus and herewith influences the torque of the ankle joint. In a nutshell you may regard the apophyses as adjusting screws acting on their adjacent joints and influencing their growth, form and structure.