Key takeaways
- Bumper damage and body damage are different questions. A low-speed rear-end hit can leave the car fine and the neck and back hurt.
- In a rear-end hit the seat pushes your torso forward while your head lags, then snaps. That motion is what strains the neck and low back.
- Being belted, headrest height, and whether you saw it coming all change what gets loaded. Tell the clinician those details.
- Get examined the same week. The exam is easier and the record is cleaner while the picture is fresh.
The commute hit is the one this bulletin hears about most. Stopped at a light on Tesson Ferry or Lemay Ferry, creeping in traffic on 55 or 270, and somebody behind you looked at their phone. The bumper took it, maybe a cracked taillight, maybe nothing. You got out, looked, shrugged, swapped information, drove home. The car was fine. Your back did not get the memo.
Half a second, in slow motion
Here is what a rear-end hit does to a body. The car you are in gets shoved forward. Your seat is bolted to the car, so your torso goes with it. Your head is not bolted to anything. For a fraction of a second it stays where it was while your shoulders move forward underneath it, which bends the neck backward. Then the head catches up and whips forward. Meanwhile the low back, which was sitting in a slight curve, gets pushed flat into the seat and then loaded as the body rebounds against the belt.
None of that needs a high speed. It needs a sudden change in speed, which is what a stopped car getting hit from behind is. The NINDS describes whiplash as a neck injury from a sudden backward and forward movement of the head, and lists rear-end crashes as a common cause. Speed changes how bad it is. It does not change whether it happens. (NINDS, whiplash.)
Why the bumper lies to you
Modern bumpers are built to absorb a hit without showing it. That is good for the car and bad for your judgment, because people use the bumper as a gauge for how hard they were hit. A bumper that springs back tells you the bumper worked. It tells you nothing about what your neck did.
So do not grade your injury by the body shop estimate. Grade it by what your neck and back do over the next three days. The second morning page explains why that is the honest timeline.
The details that change what got loaded
Were you belted. A belt holds the torso and changes how the head moves; the NHTSA is clear that belts are the single most effective thing in a car for preventing serious injury, and you should always wear one, but a belted body still takes the neck motion. Where was your headrest. A headrest set at the right height limits how far the head goes back. Did you see it coming. A braced body loads differently than a relaxed one. Were you turned, reaching for the radio, looking at the mirror. A turned neck takes the hit on one side. (NHTSA, seat belts.)
Write those details down the same evening. They are exactly what the clinician will ask, and they help the exam make sense of why the left side of your neck hurts and the right does not.
The same evening
Three things. If anything scares you, go to the emergency room. Chest pain, a sudden severe headache, weakness or numbness on one side, trouble speaking, a loss of bowel or bladder control, or a head injury with vomiting or worsening confusion is an emergency room trip right now, not a call to a clinic. If nothing scares you, note the time, the direction, and the details above. Then decide now, while you are still annoyed about the bumper, that you will call the clinic on your first break tomorrow if the morning is stiff. The after the wreck page walks the first week.
Punch in
The car got looked at. Get the back looked at.
Missouri Injury Clinic examines auto-injury patients at three rooms. The South County room on Tesson Ferry is the one most commute-hit readers can reach after a day shift.
Say it was a car crash and when. Ask for the earliest slot that fits your shift.
The commute back
A thing people do not plan for: the drive to work the next morning with a stiff neck. Checking a blind spot on the 55 merge with a neck that only turns halfway is its own hazard. Adjust the mirrors wider than usual, leave more following distance, and if the neck will not turn, that is a reason to get examined, not to power through.
And if you drive for a living, the crash has a second shift in it. Sitting in a truck seat for eight hours is one of the harder things to ask of a freshly strained low back. Tell the clinician what you drive and how long. The plan should account for it. More on that on the back on the floor page.
The short version is the same one posted everywhere on this board. Low speed does not mean low injury. The bumper does not know. Get examined this week, get the findings on paper, keep your week.