Lacrimal bone — anatomy, function, and clinical relevance

Anatomy and features

Despite its modest size, the lacrimal bone has several identifiable surfaces and margins and contributes to the formation of the nasolacrimal canal. It typically articulates with adjacent bones such as the frontal bone, maxilla and the ethmoid. The bone is thin and fragile compared with many other cranial bones.

• Lacrimal groove/fossa: a depression that, together with the maxilla, forms the nasolacrimal canal that conducts tears from the lacrimal sac to the nasal cavity.
• Posterior and anterior lacrimal crests: ridges that serve as attachment points for surrounding soft tissues and contribute to the orbital rim.
• Orbital and nasal surfaces: the two faces of the bone that border the eye socket and the nasal cavity respectively.

Development and name

The lacrimal bone develops through intramembranous ossification like many facial bones. Its small size and delicate shape can vary somewhat between individuals. Historically and etymologically, the name reflects its proximity to the tear drainage apparatus rather than any active role in tear production.

Function and clinical relevance

Functionally, the lacrimal bone helps form the bony channel that allows tears to drain from the eye into the nose; damage to this area can interfere with normal tear flow. Clinically, it is relevant in orbital fractures, congenital obstructions of the nasolacrimal duct, and inflammatory conditions of the lacrimal sac such as dacryocystitis.

Examples and notable facts

Surgical procedures addressing blocked tear drainage, for example dacryocystorhinostomy, are performed near the lacrimal bone to create an alternate pathway into the nasal cavity. Because of its small, thin nature it is sometimes fractured in blunt orbital trauma, which can produce persistent tearing (epiphora). For further basic reference see additional anatomical resources.