**Core Concept**
In cases of head injury following a trauma, particularly with altered consciousness and pupillary changes, the primary concern is to identify and manage potential life-threatening conditions such as increased intracranial pressure (ICP) or intracranial hemorrhage. The dilated pupil indicates a possible third cranial nerve (oculomotor nerve) palsy or a sign of herniation.

**Why the Correct Answer is Right**
A dilated pupil on the same side as the head injury suggests a possible compression or damage to the oculomotor nerve, which is often associated with transtentorial herniation. In this scenario, immediate assessment and management of the patient's airway, breathing, and circulation (ABCs) are crucial. The next step would be to perform a rapid and focused neurological examination, including checking the level of consciousness, pupillary responses, and fundoscopic examination to assess for signs of papilledema.

**Why Each Wrong Option is Incorrect**
* **Option A:** While maintaining ABCs is essential, it is not the next step in management given the specific clinical presentation of a dilated pupil.
* **Option B:** Administering sedatives or anesthetics without proper assessment and stabilization could worsen the patient's condition and mask important clinical signs.
* **Option C:** Imaging studies like CT scans are not available, but this option implies that a CT scan would be the next step, which is not feasible.

**Clinical Pearl / High-Yield Fact**
In cases of head injury, a dilated pupil on the same side as the head trauma often indicates transtentorial herniation. Remember the "3rd nerve" sign: a dilated pupil, ptosis, and a fixed, dilated pupil on the same side as the head injury.

**Correct Answer:** C.