Question

Which wall is most often fractured in a blow out fracture of the orbit due to a fisticuff injury?

• A. Superior wall
• B. Inferior wall
• C. Medial wall
• D. Lateral wall

Hint:

Think of the thinnest bone in the orbit, which lies over the maxillary sinus below the eye.

Answer 1

The Correct Option is B

Step 1: Recall what a blow out fracture is.
A blow out fracture happens when a blunt object, such as a fist or a ball, strikes the eye and suddenly raises the pressure inside the bony orbit. This pressure has to escape somewhere, and it breaks through the thinnest wall of the orbit rather than the sturdy orbital rim.

Step 2: Compare the thickness of the orbital walls.
The orbital floor (inferior wall) is made of thin bone over the maxillary sinus, and the medial wall (lamina papyracea) is also thin over the ethmoid sinuses. The superior wall and lateral wall are both much thicker and stronger, since the lateral wall is reinforced by the zygomatic bone and the roof by the frontal bone.

Step 3: Identify the weakest point.
Between the floor and the medial wall, the orbital floor is classically the weakest and most commonly fractured site, especially along the region near the infraorbital groove.

Step 4: Understand the clinical picture that follows.
When the floor fractures, orbital fat and sometimes the inferior rectus or inferior oblique muscle can herniate into the maxillary sinus below, causing enophthalmos (sunken eye), restricted upward gaze, and numbness of the cheek and upper lip from infraorbital nerve involvement. This clinical picture matches floor fractures specifically.

Step 5: Rule out the other walls.
The medial wall can fracture too, sometimes together with the floor, but alone it is less common as the single most fractured wall. The superior and lateral walls rarely fracture in a blow out injury because they are much thicker.

Step 6: Final answer.
The inferior wall (orbital floor) is the wall most often fractured in a blow out fracture.
\[ \boxed{\text{Inferior wall}} \]