Blow out fracture of orbit most commonly leads to fracture of
**Core Concept**
A blow out fracture of the orbit occurs when there is a fracture of one or more of the bones that form the orbit, typically due to a direct blow to the globe or indirect force transmitted through the orbital rim. This type of fracture can lead to herniation of orbital contents into the maxillary sinus or other surrounding structures.
**Why the Correct Answer is Right**
In a blow out fracture of the orbit, the thinnest wall of the orbit is most likely to fracture, which is the floor of the orbit. The floor of the orbit is formed by the maxillary bone, which is thinner and more prone to fracture compared to the other walls. The orbital floor is also more likely to fracture due to the transmission of forces from the globe or the orbital rim to the maxillary bone.
**Why Each Wrong Option is Incorrect**
**Option A:** The medial wall of the orbit, formed by the lamina papyracea of the ethmoid bone, is also a potential site for fracture, but it is not the most common site.
**Option B:** The lateral wall of the orbit, formed by the zygomatic bone and the greater wing of the sphenoid bone, is thicker and less prone to fracture compared to the floor.
**Option C:** The roof of the orbit, formed by the orbital plate of the frontal bone and the lesser wing of the sphenoid bone, is also thicker and less likely to fracture.
**Clinical Pearl / High-Yield Fact**
In a patient with a suspected blow out fracture of the orbit, it's essential to perform a thorough examination, including assessment of extraocular muscle function, to rule out other potential complications, such as optic nerve injury or entrapment of the inferior rectus muscle.
**Correct Answer:** D.