Question

A blow out fracture of the orbit most commonly involves the:

• A. Floor
• B. Medial wall
• C. Lateral wall
• D. Roof

Hint:

The thinnest orbital wall, hollowed by the infraorbital canal, is the floor.

Answer 1

The Correct Option is A

Step 1: Picture the mechanism: a blunt force compresses the globe, intra-orbital pressure spikes, and the pressure escapes by cracking the flimsiest bony wall - it "blows out".
Step 2: Rank the walls by strength. The lateral wall is robust, the roof is supported by frontal bone, and the medial lamina papyracea, though thin, is partly splinted by the ethmoid air-cell septa.
Step 3: The floor is the weak link because the infraorbital canal hollows it out, leaving sub-millimetre bone. That is why isolated blowout fractures land here.
Step 4: The tell-tale features - restricted upgaze from inferior rectus entrapment, sunken eye and cheek numbness - confirm a floor injury.
\[\boxed{\text{Floor}}\]