A 20 year old man is hit on the eye with a ball. On examination there is restriction of lateral and upward gaze and diplopia. There is no obvious visible sign of injury to the eye ball, but there is some enophthalmos, the likely diagonosis is –

**Core Concept**
The underlying principle being tested is the understanding of **orbital fractures** and their effects on **extraocular muscle** function. This involves knowledge of **anatomy** of the orbit and the relationship between the eye and surrounding structures.

**Why the Correct Answer is Right**
The clinical presentation suggests a **blowout fracture** of the orbit, where the force of the impact causes a fracture of the orbital floor or medial wall, leading to entrapment of the **inferior rectus muscle** or **medial rectus muscle**. This results in restriction of **lateral and upward gaze** and **diplopia**. The presence of **enophthalmos** supports this diagnosis, as it indicates posterior displacement of the globe.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not typically present with restriction of lateral gaze.
**Option B:** This option is incorrect because it is not directly related to the symptoms described.
**Option C:** This option is incorrect because it would not cause the specific pattern of diplopia and gaze restriction seen in this patient.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **blowout fractures** can present with **limited extraocular muscle movement** and **diplopia**, even in the absence of obvious eye injury.

**Correct Answer:** D. Blowout fracture of the orbit.

✓ Correct Answer: C. Blow out fracture of the orbit