A boy presents with diplopia and restriction of eye movements following blunt trauma to his eye. X-ray reveals blow out fracture of orbit. Which part of orbit is most likely damaged :
**Core Concept**
The question is testing the knowledge of orbital anatomy, specifically the structures that are susceptible to damage in a blowout fracture of the orbit. The orbital floor, medial wall, and lateral wall are common sites for fractures, but the most likely damaged part in this scenario is the orbital floor.
**Why the Correct Answer is Right**
The orbital floor is composed of thin bone that is more susceptible to fracture than the thicker bone of the medial and lateral walls. The orbital floor is also closer to the globe and adnexa, making it more likely to be damaged in a blowout fracture. The fracture of the orbital floor can lead to herniation of the orbital contents into the maxillary sinus, causing diplopia and restriction of eye movements.
**Why Each Wrong Option is Incorrect**
**Option A:** The medial wall of the orbit is less likely to be damaged in a blowout fracture because it is thicker and more robust than the orbital floor.
**Option B:** The lateral wall of the orbit is also less likely to be damaged in a blowout fracture because it is thicker and more robust than the orbital floor.
**Option C:** The orbital roof is less likely to be damaged in a blowout fracture because it is composed of thicker bone that is more resistant to fracture.
**Clinical Pearl / High-Yield Fact**
In a blowout fracture of the orbit, the key clinical finding is the presence of enophthalmos (sinking of the globe into the orbit) and infraorbital nerve anesthesia due to the herniation of orbital contents into the maxillary sinus.
**Correct Answer:** C. The orbital roof is less likely to be damaged in a blowout fracture because it is composed of thicker bone that is more resistant to fracture.