What are the bones of the orbit?

Seven bones make up the orbit. Click on the photograph to enlarge and test yourself by naming the numbered bones. The roof of the orbit is composed of 2 bones, the frontal bone and the sphenoid bone. The frontal bone (#1 in blue) comprises the anterior part of the roof of the orbit and the lesser wing of the sphenoid (#2 in tan) surrounds the optic canal and forms the posterior part of the roof.

The medial wall of the orbit is composed of 4 bones: sphenoid, ethmoid, lacrimal and maxillary bone. The lesser wing of the sphenoid (#2 in tan) is most posterior and is joined to the ethmoid bone (#3 in dark green), moving anteriorly to the lacrimal bone (#4 in light red) and then to the maxillary bone (#5 in light green).

The floor of the orbit is composed of 3 bones: maxillary bone (#5 light green); zygoma (#6 in pink) and posteriorly, the palantine bone (#8 in bright red). The palantine bone borders on the inferior orbital fissure, which narrows posteriorly. In radiologic studies the medial direction and narrowing are key identifiers for this fissure.

The lateral wall of the orbit is composed of the zygoma(#6 in pink) and the greater wing of the sphenoid (#7 in tan).

>