3D Anatomy of the Developing Heart: Understanding Ventricular Septation.

Understanding how the four-chambered mammalian heart is formed from a simple, looped tube remains challenging, notwithstanding the descriptive accounts left by generations of cardiac anatomists. Much of the difficulty lies in attempting to visualize an intricate series of morphological transformations through the restrictive lens of two-dimensional images derived from histology. Modern imaging methods offer a way to overcome this limitation by providing comprehensive and high-resolution image sets of the developing heart. We have used one such method, high-resolution episcopic microscopy (HREM), to obtain virtual three-dimensional (3D) models of successive stages in mouse heart development. Taking advantage of the ability afforded by 3D modeling to view each heart in any orientation or erosion plane, we provide an illustrated account of how the mouse heart divides into left and right ventricular chambers, and how each acquires its own distinct outflow vessel.