In 1895, well over 100 years ago, Willem Roux published his collected works on the developmental mechanics of organisms in 2 volumes. Volume 1 is largely dedicated to functional adaptation and is a condensation of his investigations into causes of the size and shape of organs and tissues, postulating the influence of functional demand, mediated by mechanical stimuli, on the shaping of organs and tissues. In this classic work he contributed to the understanding of the control of the structural development and organisation of blood vessels, muscles and bone. This work has been a source of inspiration for many investigators over the years. Well known examples are Wolff's law and Pauwel's theory on trajectories. Over the past 2 decades these hypotheses and concepts have been reappraised using 2 main approaches. Firstly, in muscles and tendons a qualitative approach with classical Newtonian mechanics combined with the anatomical configuration of these structures has been used to study the direction and the nature of the mechanical stresses in the tissues, be they compressive, tensile or shear. In bone and blood vessels these stresses are less accessible and often require computer modelling to calculate the mechanics at a cellular level. Secondly, molecular biology has demonstrated, both in tissue culture and in animal experiments, that mechanical stimuli can bring about cascades of messages in and between cells, but the experimental control of mechanical stresses in biological experiments is far from simple and limits the conclusions that can be derived. In order to approach a complete picture, the gap between these 2 approaches must be bridged. In this respect modern imaging techniques are helpful because they offer the possibility of studying the shape and change of shape over time in living organisms in greater detail.

The Symposium was organised in such a way that for different tissues recent advances using different approaches could be presented, helping to identify future directions for this field of morphological research. Review articles based on 2 of the 6 contributions to the Symposium are published here. One has already appeared (Benjamin & Ralphs, J. Anat. 193, pp. 481–494).