Regional Injuries MCQs

In this case, pedestrian hit by a car (Primary impact injury) hurls up on the windshield (Secondary impact injury) following which his head strikes the road (Secondary injury. Injuries to pedestrians: Primary impact injuries are the injuries sustained by a pedestrian by the initial impact with the vehicle. Secondary impact injuries are the injuries sustained by a pedestrian by falling over the vehicle. Secondary injuries (Sometimes also called as Tertiary injuries) are the injuries sustained by a pedestrian by falling over the ground after being hit by the vehicle. References: Knight's Forensic Pathology, 4 th Edition, Page No. 289; Textbook of Forensic Medicine & Toxicology, Anil Aggrawal, Page No. 355

Explanation: The head injury sustained when the head strikes the road is a Secondary injury . In the scenario described: The pedestrian is hit by the car (The injuries sustained by a pedestrian due to the initial impact are known as Primary impact injury). (Option A) The pedestrian then hurls up onto the windshield (The injuries sustained by a pedestrian by falling over the vehicle is known as Secondary impact injury). (Option B) Finally, the pedestrian's head strikes the road. The injuries sustained by a pedestrian by falling over the ground after being hit by the vehicle is known as Secondary injuries (sometimes also called Tertiary injuries). Key Takeaway: In a vehicular accident involving a pedestrian, the injury sustained from falling onto the ground after being hit by the vehicle is classified as a Secondary injury (also sometimes called Tertiary injury).

Extradural haemorrhages (EDH) cannot be ruled out in the absence of a skull fracture. Most extradural haemorrhages are associated with fractures of the skull, but about 15 per cent occur in intact skull. They usually occur unilaterally in the parieto-temporal area, caused by the rupture of the middle meningeal artery (usually posterior branch). It is the least common type of brain membrane bleeding. The most common traumatic intracranial haemorrhage is sub-arachnoid haemorrhage. Adams suggests that a minimum volume of 35 ml is needed before clinical signs are apparent, though other writers suggest 100 ml is usually the minimum associated with fatalities. Reference: Knight's Forensic Pathology, 4th edition. Page no 182, 183

Injury to the brainstem and spinal cord above C4 vertebral level (as C4 vertebrae correspond to C5 spinal level) can be rapidly fatal from disruption of cardiorespiratory regulation centres. The spinal respiratory centre (origin of the phrenic nerve) is mostly composed of the C4 segment of the spinal cord, with a smaller contribution from C3 and C5 segments.Injury to brainstem and spinal cord above C4 can be rapidly fatal from disruption of cardiorespiratory regulation centres. Reference: The Essentials of Forensic Medicine and Toxicology, 35th edition, KS Narayan Reddy, Page No. 204

Pincer contusions may be seen in trauma to the lungs. The trauma to the chest may lead to bleeding in the lungs, sometimes sufficient to form actual haematomas with breakdown of lung tissue. The expanded lower margins of the lungs become trapped in the narrow costophrenic angles causing the contusions. Reference: Knight's Forensic Pathology, 4th Edition, Page No. 219