**Question:** A young adult presents with proptosis and pain in eye after 4 days of trauma to eye. Chemosis, conjunctival congestion and extraocular muscle palsy with inability to move eye are seen. Investigation of choice -

A. CT scan
B. MRI
C. Ultrasound
D. Fundoscopy

**Correct Answer:** .

**Core Concept:** Traumatic orbital injury is a condition caused by external force applied to the orbit, which houses the eye and surrounding structures. Common findings include proptosis (enlargement of the eyeball), pain, chemosis (swelling of the conjunctiva), conjunctival congestion, and extraocular muscle palsy leading to inability to move the eye.

**Why the Correct Answer is Right:**

The correct answer is B. MRI (Magnetic Resonance Imaging). MRI is the preferred imaging modality in this scenario due to its superior soft tissue resolution and lack of ionizing radiation exposure. CT scan (option A) is also a valuable tool, but it entails ionizing radiation exposure, which can be harmful, especially in pediatric cases or those with a history of radiation exposure. MRI provides detailed imaging of the orbital structures, including the eye, optic nerve, and adjacent tissues, enabling a comprehensive assessment of the extent of orbital trauma and associated injuries.

**Why Each Wrong Option is Incorrect:**

A. CT scan (option A) is less suitable due to its radiation exposure, which can be harmful, especially for pediatric patients or those with a history of radiation exposure.

B. MRI (option B) is the right choice due to its superior soft tissue resolution and lack of ionizing radiation exposure.

C. Ultrasound (option C) is not suitable for assessing orbital trauma as it lacks the necessary resolution to visualize the orbital structures and optic nerve. Ultrasound is primarily useful in evaluating fetal or abdominal conditions.

D. Fundoscopy (option D) is a direct examination of the eye but does not provide comprehensive imaging of the orbital structures and adjacent tissues, which is crucial for assessing the extent of orbital trauma and associated injuries. Fundoscopy is primarily used for evaluating the fundus, optic nerve, and retina in ophthalmologic cases.

**Core Concept:** Traumatic orbital injuries are a result of external force applied to the orbit, causing damage to the eye, optic nerve, and surrounding structures. These injuries can lead to visual impairment, pain, and other ocular and neurological symptoms. Understanding the appropriate imaging modalities is essential for accurate diagnosis and management of these cases.

**Clinical Pearls:**

* Optic nerve injuries are potentially blinding and often require urgent intervention to prevent permanent visual loss. MRI is vital for evaluating optic nerve damage and assessing the extent of orbital trauma.
* Proper management involves a multidisciplinary approach, including ophthalmologists, neurosurgeons, and orbital surgeons, depending on the severity of injury.

**Why Each Wrong Option is Incorrect:**

A. Ultrasound (option C) is inadequate for assessing orbital injuries due to its inability to visualize the orbital structures and optic nerve.