The lacrimal bone (latin: os lacrimale) is the smallest and the thinnest bone of the skull. The lacrimal bone is a paired bone that lies anteriorly in the medial wall of the orbit.
Each lacrimal bone has two surfaces (lateral and medial) and four borders (anterior, posterior, superior, and inferior).
The lateral (orbital) surface of the lacrimal bone is divided by a vertical posterior lacrimal crest. Anterior to the lacrimal crest lies a vertical groove - the lacrimal groove.
The lacrimal groove is a groove for the nasolacrimal duct, situated in the anterior part of the lateral surface of the lacrimal bone and on the frontal process of maxilla. The lacrimal groove of the lacrimal bone fuses anteriorly with the posterior border of the frontal process of the maxilla to form the fossa that houses the lacrimal sac. The medial wall of the groove has a descending extension that contributes to the formation of the nasolacrimal canal.
The medial (nasal) surface of the lacrimal bone presents a longitudinal ridge corresponding to the lacrimal crest on the lateral surface. The anterior region of the medial surface of the lacrimal bone forms part of the middle nasal meatus.
The anterior border of the lacrimal bone articulates with the frontal process of the maxilla.
The posterior border of the lacrimal bone articulates with the orbital plate of the ethmoid bone.
The superior border of the lacrimal bone articulates with the frontal bone.
The inferior border of the lacrimal bone articulates with the orbital surface of the maxilla, while its anterior portion is prolonged downward and articulates with the lacrimal process of the inferior nasal concha, contributing to the formation of the canal for the nasolacrimal duct.