In histology, a lacuna is a small space, containing an osteocyte in bone,[1] or chondrocyte in cartilage.

In an ordinary microscopic section, viewed by transmitted light, they appear as fusiform opaque spots.

Each lacuna is occupied during life by a branched cell, termed an osteocyte, bone-cell or bone-corpuscle.

Lacunae are found between narrow sheets of calcified matrix that are known as lamellae (/ləˈmɛli/ lə-MEL-ee).

This article incorporates text in the public domain from page 90 of the 20th edition of Gray's Anatomy (1918)