Cortical bone

The substantia compacta ( compact substance ) is an expression of the bone. It forms the outer layer of the bone and is therefore also known as cortical bone ( cortical bone, from Latin cortex " bark "). Outside the cortex is covered by the periosteum ( periosteal ).

The basic component of the substantia compacta is the osteon (from Latin os, " bone "). It consists of a central channel, the Haversian canal in which runs a small blood vessel ( Haversian vessel). To this vessel channel superimposed concentric bone cells, the so-called special fins. Each osteons are interconnected by so-called lamellae. Lamellae are remnants of old, remodeled osteons. The Haversian canals of the individual osteons are also connected by blood vessels containing transverse channels ( Volkmann's canals ) with each other.