Why can the head be out of...

Why is it for FF the ears can be level with the top of the seat but for RF the head has to be 1 inch below the shell?

I get that for RF the head needs to stay in the shell to stay protected when they ramp up but does their head not matter as they get older (i.e. why is it okay when FF)

If you have watched a crash test of a RFing seat, you have seen it bows downward during a frontal impact. This is when they can ramp up in the seat and possibly hit something. In a FFing seat, that just doesnt happen. Everything flies forward in a frontal crash, so their head isn't going to ramp up.
The 'to the top of the ears' rule is so they continue to have whiplash protection. If you are rear-ended or when they rebound back into the seat during a frontal crash, then their head/neck will still be protected as needed.

Aside from the basic triumph though, I can't think of a seat that they actually make it to the tips of their ears before they have already outgrown the top slots...

i was just thinking about this the other day!! i figure that when rearfacing, if they ramp up, they must come back down, and when they do, if the back of the head is over the rim of the seat, it would catch on it, right where the cerebellum is... i believe that is where vision is?? why for ff i dont know. havent tried to wrap my mind around that one yet.

wildeyes said:

i was just thinking about this the other day!! i figure that when rearfacing, if they ramp up, they must come back down, and when they do, if the back of the head is over the rim of the seat, it would catch on it, right where the cerebullum is... i believe that is where vision is?? why for ff i dont know. havent tried to wrap my mind around that one yet.

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Vision is right at the back of the head. In the occipital lobe.

You're close, but it's not that technical. Carseats are not designed to save vision. The spinal column can stretch if the head goes over and back too far. Whiplash. I don't think it's as likely to cause internal decapitation, but I suppose if the head went too far over it could. Though most people turn their kids far before that's a problem. But say for some reason you had a big kid RFing in an old Triumph and then there was a frontal collision. Their head would go toward the point of impact with all of the force of a frontal collision.

Wendy

oh i know they arent designed to save vision, i just thought it was interesting. i'm actually suprised that #1 i remembered how to spell cerebellum, #2, that i was right in where it was and #3 that thats what was actually there. lol. it just kinda popped into my head as i was typing my response and thought id put it in and make myself seem smarter lol

Also most infants heads have a buldge off the back which if caught on the shell along with momentum of the body that keeps moving the neck would come out worst off. The injuries then are quite severe.

When forward facing the head moves backward and forward and the neck is stronger.

LOL That's how I felt about occipital. Though Piper is all about anatomy and so I've absorbed some in the process.

Wendy

<nodding in agreement with whiplash risk reduction>

I had some fun digging around at CPSPList archives and came up with this gem:

"To "pass" the 213 test, among other things, the target on the side of the
dummy's head (the center of gravity, approximately at the ears) must not
rise above the top of the shell. This is to protect against whiplash injury
from the head swinging over the top of the CR. To keep the target down
during the test, the harness needs to be threaded through slots below
the shoulders and it must be very snug.

If an actual child started out with the ears at the top of the shell, it would
be an unusual parent who would tighten the harness enough to keep the
center of gravity of the child's head from passing the top of the shell in a
severe crash, and the child's shoulders would have to be unusually stiff.
Since there will always be some ramping, and the heavier the child, the
more ramping will occur, limiting the top of the head to the top of the
shell, or a little below, is a good guideline. Other reasons exist as well,
such a containing the head to minimize head contact injury or even neck
compression.

As more people decide to keep children rear-facing longer, which would
be a very good thing, and there is a demand for RF CRs with higher
backs, more manufacturers will provide them. In the meantime, best
practice doesn't change.

KW

*********************
Kathleen Weber
SafetyBeltSafe U.S.A.
Technical Advisor"

wendytthomas said:

Vision is right at the back of the head. In the occipital lobe.

You're close, but it's not that technical. Carseats are not designed to save vision. The spinal column can stretch if the head goes over and back too far. Whiplash. I don't think it's as likely to cause internal decapitation, but I suppose if the head went too far over it could. Though most people turn their kids far before that's a problem. But say for some reason you had a big kid RFing in an old Triumph and then there was a frontal collision. Their head would go toward the point of impact with all of the force of a frontal collision.

Wendy

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Thanks for this info! i've wondered the same thing for quite some time. By the way, I love your daughter's name!

Wynters*Mom said:

Thanks for this info! i've wondered the same thing for quite some time. By the way, I love your daughter's name!

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Thanks! I love your daughter's name. LOL I love the nature-y names, Winter/Wynter, Autumn, Summer, Willow, Rayne, etc, but my husband doesn't. I had Willow on my list for a long time. I think Piper could have been a Willow. But not too much else. She's definitely is a Piper.

Wendy