Flat Head Syndrome (Plagiocephaly) in Babies: When Should You See an Osteopath?

We talk about positional plagiocephaly when a baby’s skull flattens in one spot from resting in the same position again and again. It has become more common since babies started sleeping on their backs - an essential safety measure that has dramatically reduced sudden unexpected infant death, and one you should absolutely not give up.

Plagiocephaly, brachycephaly: what’s the difference?

Plagiocephaly is a flattening on one side of the back of the skull: seen from above, the head takes on a slight parallelogram shape. Brachycephaly is a symmetrical flattening across the whole back of the head, which makes the head look wider. In both cases, it’s a position-related deformation, not a problem with the bone itself.

Why the skull flattens

Several factors often combine: your baby’s preferred sleeping position, a slightly stiff neck that keeps them looking the same way (a torticollis), time spent in bouncers, infant seats, and car seats, or a particular position during pregnancy.

The best vantage point is from above, looking down at your baby’s head. A few things to look for:

• One side of the back of the skull flatter than the other
• A baby who almost always turns their head to the same side

Everyday habits are what make the biggest difference, especially when you start early. The general idea: reduce pressure on the same spot, and encourage your baby to turn their head both ways.

At night: always on the back, and nothing in the crib

Keep putting your baby to sleep on their back: that’s the essential safety rule. No pillows, no “anti-flat-head” positioners - these devices carry a suffocation risk and are not recommended. What you can do is alternate the direction you lay your baby down, so they spontaneously turn their head to one side and then the other.

During the day: tummy time, under your watchful eye

When your baby is awake and supervised, place them on their tummy several times a day, starting in the very first weeks, a few minutes at a time. Tummy time strengthens the neck and takes pressure off the back of the skull. Vary the stimulation too: change the side you place toys on, switch the arm you carry your baby with, and favor babywearing over the bouncer.

Nursing, bottles, diaper changes: the little habits that count

Remember to alternate sides during breastfeeding or bottle-feeding, and to position your face sometimes to the right, sometimes to the left during diaper changes. Limit time spent in infant seats and car seats outside of car rides. These tiny adjustments, repeated every day, are often what helps most.

Very often, a flat head comes with a slightly stiff neck: the baby turns their head more easily to one side, nurses better on one breast, or always tilts their head the same way. Spotting this torticollis matters, because as long as it persists, the pressure stays on the same side and the head has a hard time rounding out. This is precisely one of the areas where infant osteopathy can help, alongside positioning advice.

The earlier you act, the more effective it is, because the skull takes its shape mostly during the first months, while it’s growing fast. From the very first weeks, if you notice a flat spot or a stiff neck, that’s the right time to start varying positions and ask for a professional opinion. A cranial helmet remains an exceptional measure, decided by specialized teams - never a first step.

At my practice in Katamon, I welcome babies from Jerusalem’s English-speaking and international community, with sessions in English or French and parents present the whole time. I work hand in hand with your pediatrician and Tipat Halav. If the shape of your baby’s head is on your mind, send me a message: we’ll look at it together, calmly, and see what can help.