Blow out fracture affects which orbital wall ?
**Core Concept**
A blow out fracture refers to a type of orbital fracture characterized by the displacement of the orbital floor or medial wall, resulting from increased intraorbital pressure. This condition often occurs due to a direct blow to the globe or orbit, leading to a sudden increase in pressure within the orbit.
**Why the Correct Answer is Right**
The orbital floor is the most commonly affected wall in a blow out fracture, as it is the weakest point of the orbit. This is due to the relatively thin bone structure of the orbital floor, which is composed of the maxillary bone and the palatine bone. The increased intraorbital pressure causes the orbital floor to fracture, leading to herniation of the orbital contents, including the inferior rectus muscle, into the maxillary sinus. This can result in a range of complications, including diplopia, enophthalmos, and infraorbital nerve paresthesia.
**Why Each Wrong Option is Incorrect**
**Option A:** The lateral wall of the orbit is not typically affected in a blow out fracture, as it is relatively strong and composed of the zygomatic bone and the frontal process of the maxilla.
**Option B:** The superior wall of the orbit is not affected in a blow out fracture, as it is composed of the frontal bone and is relatively strong.
**Option C:** The medial wall of the orbit can be affected in a blow out fracture, but it is not as common as the orbital floor. The medial wall is composed of the lacrimal bone and the ethmoid bone.
**Clinical Pearl / High-Yield Fact**
It is essential to diagnose and manage blow out fractures promptly to prevent long-term complications, such as enophthalmos, diplopia, and infraorbital nerve paresthesia. A thorough clinical examination and imaging studies, including CT scans, are necessary to confirm the diagnosis and plan appropriate treatment.
**Correct Answer:** C. The medial wall.