lacrimal sac

lacrimal sac, the upper end of each of the two nasolacrimal ducts. Each sac is lodged in a deep groove formed by the lacrimal bone and the frontal process of the maxilla. The sac is ovoid and about 13 mm long. Its upper end is closed and rounded, its lower end continuous with the nasolacrimal duct. The lacrimal sacs fill with tears secreted by the lacrimal glands and conveyed through the lacrimal ducts.