**Core Concept**
Back examination of a polytrauma patient is crucial to assess potential spinal cord injuries, which can be catastrophic if not recognized and managed promptly. The examination involves evaluating the patient's neurological status, spinal stability, and potential deformities or tenderness in the spine.

**Why the Correct Answer is Right**
The back examination of a polytrauma patient is typically done using the log roll method, also known as the log roll technique. This method involves carefully rolling the patient onto their side while maintaining spinal alignment and control, allowing for a thorough examination of the spine without causing further injury. The log roll method is essential to prevent exacerbating any potential spinal cord injuries and to ensure the patient's safety during the examination.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the log roll method is the preferred technique for back examination in polytrauma patients, whereas other methods may not provide adequate spinal control or may cause further injury.

**Option B:** This option is incorrect because the prone position is not suitable for back examination in polytrauma patients, as it may cause spinal flexion and exacerbate potential injuries.

**Option C:** This option is incorrect because the lateral position, while sometimes used for back examination, does not provide the same level of spinal control and safety as the log roll method.

**Clinical Pearl / High-Yield Fact**
When performing the log roll examination, it is essential to have a minimum of two people assisting, one to support the patient's head and neck and the other to control the patient's lower limbs, to maintain spinal stability and prevent further injury.

**Correct Answer: C. Lateral position**