**Core Concept**
Blow out fracture of the orbit is a type of fracture that involves the bones of the orbital rim or the floor and medial wall of the orbit. This occurs due to a sudden increase in intraorbital pressure, often resulting from a direct blow to the globe or a sudden change in pressure within the orbit.

**Why the Correct Answer is Right**
The orbital floor and medial wall are composed of thin bones, specifically the maxillary bone and lacrimal bone, which are more susceptible to fracture. The orbital rim, composed of the frontal bone, zygomatic bone, and maxillary bone, can also be involved in blow out fractures. The fracture occurs when the pressure within the orbit exceeds the structural integrity of these thin bones, leading to a "blow out" or displacement of the bones.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because it does not specify the bones involved in blow out fractures. While the orbital bones are indeed fragile, the question is asking for a specific type of fracture.

**Option B:**
This option is incorrect because it mentions a fracture of the orbital rim, which can occur in various types of orbital fractures, not specifically blow out fractures.

**Option C:**
This option is incorrect because it mentions a fracture of the orbital roof, which is a type of orbital fracture that involves the frontal bone and is not characteristic of blow out fractures.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that blow out fractures often present with enophthalmos (posterior displacement of the globe), limited upward gaze, and infraorbital nerve anesthesia due to the involvement of the orbital floor and medial wall.

**Correct Answer:** D.