The smallest facial bones are the lacrimal bones

The lacrimal bones are the smallest facial bones. Merrill’s Atlas names them the smallest bones in the skull, and it describes each as very thin and about the size of a fingernail. The tiny ear ossicles sit inside the temporal bone and aren’t facial bones, so they aren’t part of this comparison.

Where are the lacrimal bones?

There are two, one in each orbit. Each sits at the front of the medial orbital wall, between the ethmoid bone and the maxilla. With the maxilla, it forms the fossa that holds the lacrimal sac.

What about the nasal bones?

The nasal bones are small as well. Bontrager’s and Merrill’s both say their size varies between people, and Bontrager’s notes they can be quite small. Bontrager’s doesn’t rank the two pairs. It groups them as the thinnest and most fragile bones in the body, and it gives the lacrimal bones the same fingernail comparison.

So the positioning textbooks don’t conflict, but only Merrill’s states the ranking. No source we opened names the nasal bones as the smallest.

What are the 14 facial bones?

There are 6 pairs and 2 single bones.

Bone	Count
Maxillae	2
Zygomatic	2
Lacrimal	2
Nasal	2
Inferior nasal conchae	2
Palatine	2
Vomer	1
Mandible	1

Does this matter for the registry?

Facial bones and nasal bones are on both ARRT® outlines, but as projection lists. The outlines don’t list facts about bone size, and they don’t give ARRT’s questions. Treat this as anatomy to know, not as a promised question.

The projections are what you’ll position. Start with the lateral nasal bones and lateral facial bones pages. Our free skull, facial bones and sinuses chapter goes through the anatomy with figures, and the Procedures guide shows how it fits the exam. You can test yourself with the head, spine and pelvis questions.