The growth of elastic cartilage

Level lines of the specific growth rate and field lines of the gradient of the specific growth rate of developing ear cartilage have been computed. A single centre of maximum specific growth rate occurs in the midline and moves with time from the tip towards the base. Its movement is consistent with the progressive increase in area of the ear cartilage and with its consequent changes in form. The relationships of the centre for maximum specific growth rate to other maxima for the rates of production of cellular material, intercellular material, cell surface area and for material derivatives of intercellular volume fraction, cell volume fraction and cell surface density are discussed.