Lacuna (histology)

In histology, a lacuna (plural: lacunae) refers to a small space or cavity within a tissue. These spaces are typically occupied by cells, such as osteocytes in bone or chondrocytes in cartilage. The lacuna provides a sheltered environment for the cell and allows it to communicate with surrounding tissues via canaliculi.

Lacunae are not simply empty holes; they are specifically shaped to accommodate the resident cell and are often interconnected by a network of tiny channels called canaliculi. These canaliculi radiate outward from the lacuna, allowing the cell within to receive nutrients and eliminate waste products through diffusion with the surrounding matrix.

The appearance and distribution of lacunae are important diagnostic features in identifying different tissue types, particularly bone and cartilage. The presence or absence, shape, and arrangement of lacunae, along with the cells they contain, can aid in the differentiation of various tissue abnormalities or diseases observed under a microscope.