Atlas of plant and animal histology

This image is from osteonic compact bone. Compact bone shows no vascular cavities similar to those found in the trabecular bone. In the compact bone, lamellae are organized in more or less straight lines or in cylinders called osteons (only in some mammal species). The bone with osteons is known as osteonic bone.

The extracellular matrix of the osteonic bone is organized in lamellae, which are 3 to 7 µm thick. Lamellae are arranged concentrically around a channel, which is referred to as Haversian channel, that contains blood vessels and nerves. Osteocytes, the mature bone cells, are located in cavities named lacunae, which are also arranged around the Haversian canal. Lacunae, as well as osteocytes, are interconnected by a network of thin ducts, the bone canaliculi, enabling communication between osteocytes and the Haversian canal. Unlike others tissues, nutrients do not diffuse through compact bone extracellular matrix and that is why these canaliculi keep alive the compact bone tissue. Lamellae, canaliculi, and osteocytes that are located around the same Haversian canal are together known as osteon (Haversian canal included). Osteon is the structural unit of osteonic compact bone. There are from 4 to 20 lamellae per osteon and the osteon size is variable.