Which statement about the orbital floor is NOT true?

Which statement about the orbital floor is NOT true?

• A. The floor contains the ethmoid bone.
• B. The floor is formed by the maxillary, palatine, and zygomatic bones.
• C. The orbital floor is the weakest part of the orbit.
• D. The orbital floor contributes to the bottom boundary of the orbit.

Answer: (A)

The orbital floor is built mainly from the maxilla, with contributions from the palatine and zygomatic bones, forming the bottom boundary of the orbit. The ethmoid bone does not form the floor; its orbital plate becomes part of the medial wall (the lamina papyracea). This is why the statement that the floor contains the ethmoid bone is not true. The floor’s thin composition is why it’s often described as the weakest part of the orbit, and blows to the eye can cause a floor fracture with herniation of orbital contents.

The orbital floor is built mainly from the maxilla, with contributions from the palatine and zygomatic bones, forming the bottom boundary of the orbit. The ethmoid bone does not form the floor; its orbital plate becomes part of the medial wall (the lamina papyracea). This is why the statement that the floor contains the ethmoid bone is not true. The floor’s thin composition is why it’s often described as the weakest part of the orbit, and blows to the eye can cause a floor fracture with herniation of orbital contents.