**Question:** Enophthalmos caused by fracture of -

A. Orbital floor
B. Medial wall
C. Lateral wall
D. Supraorbital rim

**Core Concept:** Enophthalmos is a condition characterized by a sunken appearance of the eye, resulting from abnormal orbital volume or displacement of orbital contents. Enophthalmos can be caused by various orbital injuries or fractures, including those involving the orbital walls.

**Why the Correct Answer is Right:** Enophthalmos resulting from fracture is typically due to damage to the orbital floor, which houses the orbital contents such as the eye, lacrimal gland, and the orbital fat. When the orbital floor is fractured, it causes displacement of these structures, leading to the characteristic enophthalmos.

**Why Each Wrong Option is Incorrect:**

A. Orbital floor fracture: As mentioned, fractures to the orbital floor are the primary cause of enophthalmos. While fractures to other orbital walls (medial, lateral, and superior) can occur, they are less likely to cause enophthalmos due to the different structures they involve and their relative stability.

B. Medial wall fracture: The medial wall houses the lacrimal gland, but it does not directly contribute to the enophthalmos. The medial wall is more prone to fractures due to its thin structure, but it is less likely to cause enophthalmos compared to the orbital floor.

C. Lateral wall fracture: Similar to medial wall fractures, lateral wall fractures do not directly cause enophthalmos as they involve the bony structures supporting the lateral rectus muscle and the lacrimal sac.

D. Supraorbital rim fracture: The supraorbital rim is a part of the frontal bone, which is not directly involved in the pathogenesis of enophthalmos. Fractures to the supraorbital rim may cause orbital haematoma or soft tissue swelling, but it is less likely to cause enophthalmos compared to the orbital floor.

**Clinical Pearl:** Enophthalmos is a valuable clinical sign in diagnosing orbital fractures, especially in cases where the fracture cannot be visualized on imaging studies. A thorough clinical examination should be performed when evaluating patients with facial trauma, including checking for enophthalmos to aid in diagnosing and managing orbital fractures.

**Core Concept:** Enophthalmos is primarily caused by fractures involving the orbital floor, which leads to displacement of the orbital contents and resulting in the sunken eye appearance. Other orbital wall fractures may cause complications such as orbital haematoma or soft tissue swelling, but they are generally less likely to result in enophthalmos.