Blow out fracture orbit is characterized by all, except
**Core Concept**
A blow out fracture of the orbit refers to a type of fracture where there is a break in one or more of the bones that surround the eye socket. This occurs due to a sudden increase in intraorbital pressure, often resulting from a severe facial trauma or a direct blow to the eye or orbit.
**Why the Correct Answer is Right**
The correct answer will be related to the characteristic features of a blow out fracture of the orbit. A blow out fracture typically involves a fracture of the orbital floor or medial wall, which can lead to herniation of the orbital contents into the maxillary sinus or ethmoid sinus. This can cause symptoms such as enophthalmos, diplopia, and limited extraocular movement.
**Why Each Wrong Option is Incorrect**
* **Option A:** Blow out fractures can indeed involve the orbital floor, which is a common site for this type of fracture.
* **Option B:** The medial wall of the orbit can also be involved in a blow out fracture, although this is less common than a floor fracture.
* **Option C:** Blow out fractures can also involve the orbital rim, which can lead to displacement of the orbital contents and enophthalmos.
**Clinical Pearl / High-Yield Fact**
A key feature of a blow out fracture is the presence of enophthalmos, which is the posterior displacement of the globe of the eye. This is due to the herniation of the orbital contents into the maxillary sinus or ethmoid sinus, which can lead to a decrease in the volume of the orbit.
**Correct Answer: A.**