lacunarcanalicular

The lacunar-canalicular system (LCS) is a network of microscopic spaces and channels within mineralized bone that houses osteocytes and their processes, enabling communication, nourishment, and mechanotransduction. Lacunae are small cavities containing osteocytes, while canaliculi are slender channels that radiate from lacunae to connect with neighboring lacunae and with the bone surface. The canaliculi contain pericellular fluid and the cytoplasmic extensions of osteocytes, which communicate via gap junctions.

The LCS serves as the primary route for exchange of nutrients and metabolic waste between osteocytes and the vascular system embedded in bone. It also mediates mechanotransduction, translating mechanical loads into biochemical signals that regulate bone remodeling. Fluid flow within the system, driven by loading and unloading of bone, is thought to influence the activity of osteoblasts and osteoclasts through signaling pathways and molecules such as sclerostin, RANKL, and OPG.

Developmentally, osteocytes originate from osteoblasts that become embedded in the mineralizing matrix, forming lacunae; their processes extend to form canaliculi, creating an interconnected network that permeates much of cancellous and cortical bone, including within osteons of cortical bone.

Clinically, changes in the lacunar-canalicular network are associated with aging and osteoporosis and can reflect altered bone quality and mechanosensitivity. Studying the LCS remains important for understanding bone health, remodeling dynamics, and responses to mechanical load.