**Core Concept**
The initial management of blunt trauma abdomen involves a rapid assessment to identify potential life-threatening injuries and to prevent further deterioration. This is achieved through a combination of clinical evaluation, laboratory tests, and imaging studies. The goal is to identify patients with unstable injuries that require immediate surgical intervention.

**Why the Correct Answer is Right**
The first step in managing blunt trauma abdomen is to perform a focused assessment with sonography for trauma (FAST) examination. This bedside ultrasound examination helps to detect free intraperitoneal fluid, which is often indicative of internal bleeding. The FAST examination is a quick and non-invasive tool that can be performed simultaneously with other resuscitative efforts. It helps to identify patients who may require further imaging studies or immediate surgical intervention.

**Why Each Wrong Option is Incorrect**
**Option A:** **Laparotomy** is not the first step in managing blunt trauma abdomen. While it is a crucial intervention for patients with unstable injuries, it is typically reserved for those with clear evidence of significant internal bleeding or other life-threatening conditions.

**Option B:** **CT scan** is not the initial imaging modality of choice in blunt trauma abdomen. While CT scans provide valuable information about internal injuries, they are typically reserved for patients who are stable and do not require immediate surgical intervention.

**Option C:** **X-ray** is not a reliable tool for evaluating blunt trauma abdomen. While X-rays can help identify some types of injuries, such as rib fractures or pneumothorax, they are not sensitive enough to detect many other types of internal injuries.

**Clinical Pearl / High-Yield Fact**
In patients with blunt trauma abdomen, a negative FAST examination does not rule out the presence of significant internal injuries. A negative FAST examination should not delay further evaluation and treatment.

**Correct Answer:** C. X-ray