Flat Behind
Baby's Ear:
Normal?
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The full narration of the video.
There's a hard bump of bone behind your ear. Your baby doesn't have one. Washing their baby's hair, many parents feel that flat spot behind the ear. And they worry: is the head growing wrong? Try this first. Put a finger behind your own earlobe, and slide it up a little.
Feel that hard little bump? Every adult has one. Now gently feel the same spot on your baby: flat. No bone is missing. The bump just hasn't been pulled out yet.
Turn your head to one side in a mirror, and a thick muscle pops out along your neck. It starts at your collarbone, and runs all the way up to that bump behind your ear. In a newborn, this muscle has barely done any work: the head is too heavy to lift.
Once the baby starts lifting their head and turning to find you, this muscle tugs on the bone behind the ear, day after day. It's a bit like the calluses on a tennis player's hand. Grip the racket every day, and the skin thickens right where you squeeze hardest.
That's how the body works: wherever it's pulled the most, it builds a little more. A callus is thicker skin. Behind the ear, it's bone, pulled into a pointed bump. This bump has a name: the mastoid process. It starts to show after age one, and you can feel it clearly around age two.
The gripping hand is that head-turning muscle. The callus is the mastoid behind the ear. So a flat spot behind the ear just means your baby is young. It says nothing about head shape. So where should you look for head shape? The back of the head.
A baby's skull is soft. Always lying the same way flattens that side. It's very common: about half of two-month-olds have a flat spot. Most are mild. Keep putting them to sleep on their back, but switch which way the head faces. When they're awake, give them more tummy time.
Lifting the head on the tummy takes pressure off the back of the head, and trains the very muscle that pulls out the mastoid. If one side behind the ear actually bulges, or the flat spot hasn't changed after a month or two, see a doctor. That flat spot behind the ear is just waiting for them to lift their head.
How old was your baby when they first held their head up on their own?
You have a bump.
Your baby doesn't.
You're washing your baby's hair and feel a flat spot behind the ear. Your heart skips: is the head growing wrong?
Try this first. Put a finger behind your own earlobe and slide it up a little. Feel that hard little bump? Every adult has one. Now gently feel the same spot on your baby: flat.
No bone is missing. The bump just hasn't been pulled out yet.
A muscle
pulls it out
Turn your head to one side in a mirror, and a thick muscle pops out along your neck. It starts at your collarbone and runs all the way up to that bump behind your ear.
In a newborn, this muscle has barely done any work: the head is too heavy to lift. Once the baby starts lifting their head on their tummy and turning to find you, this muscle tugs on the bone behind the ear, day after day.
Like a tennis
player's callus
That's how the body works: wherever it's pulled the most, it builds a little more.
It's the mastoid.
Clear by about two.
The gripping hand is that head-turning muscle. The callus is the mastoid process behind the ear.
So a flat spot behind the ear just means your baby is young. It says nothing about head shape.
The soft spot on top of the head is unfinished bone too: see this one.
Check the back
of the head
A baby's skull is soft. Always lying the same way flattens that side.
It's very common. A Canadian study of 440 healthy babies found about half had a flat spot at around two months, and nearly 8 in 10 of those were mild.
Lifting the head on the tummy takes pressure off the back of the head, and trains the very muscle that pulls out the mastoid. Why little babies are so floppy: see this one.
Two signs
to see a doctor
No change in 2 months If one side behind the ear actually bulges, or the flat spot hasn't changed after a month or two of adjusting, see a doctor. The first is rare, and a doctor needs to check the skull seams. Follow your doctor's advice.
Quick check
Why does the spot behind a baby's ear feel flat?
That bump is the mastoid. A neck muscle pulls it out as the baby lifts and turns their head; it's clear around age two.
