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Road traffic injuries — pedestrian, driver, passenger and motorcyclist
In a road collision the pattern of injuries tells the story: in a pedestrian, "bumper" fractures of the legs show the height and direction of impact, in belted occupants seat-belt marks and aortic rupture show deceleration, and in motorcyclists the head decides the outcome.
Why it matters in the exam
Many questions ask for the most important finding from a medicolegal point of view. In a pedestrian struck by a car, the primary impact is the bumper against the legs, and at autopsy the fracture's height above the heel is measured and compared with bumper height; hard braking lowers the front of the car and therefore the impact height. A wedge-shaped (Messerer) fracture of the tibia shows direction: the base of the wedge is on the side of impact and the apex points in the direction of the vehicle's travel. Then comes secondary impact with the bonnet and windscreen, and finally tertiary impact with the road — sometimes the one that causes the fatal head injury.
In occupants, in a frontal collision the seat belt prevents ejection but leaves an oblique abrasion and bruise across the shoulder, chest and abdomen, and can cause bowel and mesenteric injury and lumbar vertebral fracture. The common fatal injury in belted occupants in a high-speed frontal collision is rupture of the aorta at the isthmus — where the fixed arch meets the mobile descending aorta — from sudden deceleration. In a driver, injuries of the hands and feet — for example a pedal imprint on the sole — and the direction of the seat-belt mark help determine who was driving.
In motorcyclists the lower limbs are injured most often, but most deaths result from head injury; a transverse "hinge" fracture across the skull base with contusions of the cerebrum, cerebellum and brainstem fits a broad blow to the side of the head. It is also important to think of a medical event that caused the crash — myocardial infarction, seizure or hypoglycaemia — and of alcohol and drugs; toxicology samples are therefore taken from both driver and pedestrian.
Key points
- Pedestrian: bumper fractures of the legs show height and direction.
- Belted occupant in a frontal collision: aortic rupture at the isthmus.
- Driver: a pedal imprint and the seat-belt mark identify the seating position.
- Motorcyclist: lower limbs common, head fatal.
- Toxicology and exclusion of a medical event in every victim.
Summary table
| Victim | Key finding | What it shows | Autopsy action |
|---|---|---|---|
| Pedestrian | Bumper fractures of the legs | Bumper height, direction, braking | Measure height from heel; look for a wedge |
| Belted occupant | Seat-belt mark, aortic rupture at the isthmus | Sudden deceleration | Examine bowel, mesentery and vertebrae |
| Driver | Hand injuries, pedal imprint on the sole | Who was driving | Examine shoes and soles |
| Motorcyclist | Lower limbs common; head fatal | Broad blow to the side of the head | Look for a basal hinge fracture |
| Any victim | Medical event, alcohol, drugs | What caused the crash | Toxicology and cardiac histology |
Free exam questions
בכביש 25 לכיוון צומת שוקת אירעה תאונת 'פגע וברח'. בעצם השוק של הולך רגל שנפגע מהרכב נמצא שבר טרנסוורסלי פתוח (שבר במישור הניצב לציר האורך של העצם), בגובה 45 ס"מ מהעקב. מה ניתן להסיק מהממצא? (the question as examined, in Hebrew)
- א. כי אותה הרגל לא נשאה את משקל הגוף. מכאן שלא ניתן להקיש לגבי גובה הפגוש של הרכב
- ב. כי גובה פגוש הרכב הפוגע הוא כ-45 ס"מ
- ג. כי גובה פגוש הרכב הפוגע גבוה מ-45 ס"מ
- ד. על כך שמהירות הרכב הפוגע הייתה נמוכה מ-50 קמ"ש בעת הפגיעה
רוכב אופנוע בן ,40 עם השמנת יתר ניכרת וללא רקע רפואי ידוע אחר, הובא לאחר תאונת דרכים. הונשם בחדר הטראומה, תוך מתן 140mg ROCURONIUM ו- 30mg .ETOMIDATE בנוסף, קיבל אנטיביוטיקה, חיסון טטנוס MORPHINE -ו. הפצוע השלים הערכה בחדר הטראומה והוא שמור המודינמית, מונשם בקלות ומחמצן היטב. כיצד יש לנהל את המשך הסדציה של הפצוע לצורך השלמת CT? (the question as examined, in Hebrew)
- א. הודות למשך הפעולה הארוך של רוקורוניום, אין צורך בתוספת הרדמה לחצי השעה הקרובה
- ב. דריפ MIDAZOLAM במינון של 0.05 מ"ג לדקה
- ג. חישוב SCORE RASS לפני מתן טיפול נוסף
- ד. דריפ PROPOFOL במינון של 12 מ"ג לדקה
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Sources
- Knight's Forensic Pathology, 4th edition (2016) — Transportation injuries
- Spitz and Fisher's Medicolegal Investigation of Death, 5th edition (2020) — Motor vehicle collisions and pedestrian injuries
- Simpson's Forensic Medicine, 14th edition (2020) — Transportation medicine
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.