Lacunes

Lacunes (or lacunae in singular) are small spaces or cavities within a tissue. The term comes from the Latin lacuna, meaning a gap or pit. In histology, lacunae are spaces that house cells. In bone, osteocytes reside in lacunae, which are arranged in a network connected by tiny channels called canaliculi that enable nutrient exchange and signaling. In cartilage, chondrocytes occupy lacunae within the extracellular matrix.

A well-known clinical use of the term is lacunar infarcts. These are small, subcortical strokes caused by occlusion of penetrating arteries, typically ranging from a few millimeters up to about 15 millimeters in diameter. They produce discrete cavitary lesions on imaging, often in the internal capsule, basal ganglia, thalamus, or pons. Lacunar infarcts are a manifestation of cerebral small vessel disease and are associated with risk factors such as hypertension and diabetes. Clinically, they may cause pure motor or sensory deficits, or be clinically silent, depending on their location and size.

The concept of lacunae also appears in other tissues and contexts where small cavities exist or form during development or disease. In histology beyond bone and cartilage, lacunae describe spaces occupied by various cell types, and in pathology they may reflect normal aging, remodeling, or pathological changes.

In summary, lacunes denote small cavities within tissues; in medicine the term often highlights small brain infarcts due to small vessel disease, while in histology they describe cell-housing spaces in bone, cartilage, and other tissues.