This shows various planes in cross and longitudinal section through all levels of the bone an well as a two plane section through the inner structure of the bone marrow. Model showing a three-dimensional section of lamellar bone, shows a typical structure of a tubular bone enlarged it 80 times. The typical elements of a lamellar bone are easily identified and helps to understand its structure and functions with its characteristic osteons also known as Haversian Systems. The model illustrates the interplay of the individual components such as spongi and compact substance, endosteun, cortical substance, osteocytes, Volkman and Haversian canals.