In the last two decades, there has been very active cooperation between cardiac surgeons and computational engineers in the field of congenital heart disease [1–3]. Cardiac surgeons are moving from traditional attitudes towards a new way of thinking which necessitates interdisciplinary integration and sharing of knowledge to understand the complex interaction between structure and function generating a specific behaviour in the biological systems. Excellence in cardiac surgery is in the operating theatre, but more and more sections of the road to excellence will be created outside the operating room. Structure, form and function in any organ are inseparable and interdependent, and the integration of knowledge concerning these three elements is an essential prerequisite in clinical evaluation and treatment of different heart diseases. To understand the connection between form and function, we must bear in mind Somer and Johnson’s statement that ‘relating structure to function in any organ,...leads inevitably to ontogeny and phylogeny’ [4] and the need to expand our understanding from ‘genes to cells to the whole organ’ [5, 6]. Surgical interventions often aim at recovering functionality of an organ or a system. In many such cases, the relevance of form (and shape) to function needs to be taken into due account. In fact, functionality depends to varying degrees on form. For instance, in organisms with a chirally asymmetrical body architecture (as is the case in over 90% of animals, including man) the relative (asymmetrical) position of organs is often important for their functions. Therefore, there has been growing interest in unravelling the genetic basis of chirality. Recent research has demonstrated the role of Nodal signalling in left–right asymmetry in several animals from snails to mammals (including man) [7–9]. Snails in particular have recently proved to be an interesting model organism. In these animals, the chirality of the shells (right-handed vs. left-handed) is a sign of their situs, similar to the heart and associated vessels that mark the situs in vertebrates. Nodal is expressed on the embryo’s right side in right-handed species and on the left side in left-handed species [8]. Nodal signalling is therefore a conserved pathway involved in normal and abnormal morphogenetic mechanisms of chirality in snails and the human body, including the spiral coiling of the shells and the spiral pattern of the cardiac outflow tract and great arteries [7–9]. The cardio-circulatory system is a beautiful example of the relevance of form to function. In individuals with situs solitus, the right ventricular outflow tract of the heart is anterior and rightsided while the pulmonary trunk runs to the left and posteriorly. The left ventricular outflow tract arises posteriorly and left-sided, while the aorta, crossing posteriorly, becomes right-sided. The comprehensive aspect of the cardiac outflow tract results in a right-handed spiral pattern with a clockwise rotation seen from the apex. In individuals with situs inversus totalis all internal organs of the body, including the heart, present a ‘mirror image’ structure and the cardiac outflow tract presents a left-handed spiral pattern with a counter clockwise rotation. It is noteworthy that organisms with inverted chirality, i.e. with situs inversus totalis, are usually vital. However, when chirality is altered in only some aspects, this can be severely noxious, or even lethal. This occurs in snail embryos following pharmacological inhibition of Nodal signalling, where shell chirality is lost resulting in a straight non-spiralized shell [8], but also in humans affected by transposition of the great arteries (TGA) with their straight non-spiralized phenotype of the great arteries [10–12]. These observations support our previous suggestion that TGA may be considered in the pathogenetic group of lateralization defects [13]. It is as if shape must be maintained because it is relevant to function: if, when inverted, it maintains its functionality, shape keeps its importance. This is what happens in snails. The role of a spirally coiled shell in gastropods (the group of molluscs to which snails belong) is still unclear. All molluscs (clams, octopuses, snails, tusk-shells and other less-known relatives) show internal anatomical asymmetries overimposed on a primarily bilaterally symmetrical bodyplan. In gastropods, left–right asymmetry is present in the internal organs but is markedly evident in the direction of coiling of their shells. In fact, while in a Nautilus (which is a