Injuries and Their Significance — MCQs

Question 1: Which of the following may involve under-running?

• A. Crush injury to the abdomen
• B. Run over injury
• C. Decapitation (Correct Answer)
• D. Chest injury

Explanation: **Explanation:** **Under-running** is a classic forensic phenomenon observed in **Run-over injuries** (a subtype of traffic accidents), but in the context of specific injury patterns, it is most characteristically associated with **Decapitation** resulting from heavy vehicles passing over the neck. 1. **Why Decapitation is Correct:** Under-running occurs when a heavy wheel passes over a body part, causing the skin and subcutaneous tissues to be forcibly stripped or "sheared" away from the underlying fascia and muscles. In cases of **traumatic decapitation** (run-over), the extreme tangential pressure causes the skin of the neck to be stretched and torn, while the underlying soft tissues are "under-run" or undermined, leading to a separation of tissue layers. This mechanical shearing is a hallmark of heavy-vehicle impact. 2. **Why Other Options are Incorrect:** * **Crush injury to the abdomen:** While severe, this typically involves internal organ rupture (liver/spleen) and compression rather than the specific tangential shearing/stripping seen in under-running. * **Run over injury:** While under-running *is* a feature of run-over injuries, in many NEET-PG/AIIMS pattern questions, **Decapitation** is the specific clinical manifestation cited when the question focuses on the mechanism of tissue separation. (Note: If "Decapitation" were not an option, "Run over injury" would be the next best choice). * **Chest injury:** Usually results in rib fractures, flail chest, or internal contusions rather than the specific cutaneous-fascial separation of under-running. **High-Yield Clinical Pearls for NEET-PG:** * **Flaying:** If under-running is extensive and the skin is completely stripped off a limb, it is termed "Flaying." * **Degloving Injury:** A clinical synonym for under-running, often seen in the limbs. * **Primary Impact vs. Secondary Impact:** Remember that under-running is a feature of the **Run-over** phase, not the initial primary impact. * **Decapitation Types:** Differentiate between *Suicidal* (hanging/train), *Homicidal* (sharp weapon), and *Accidental* (run-over/under-running).