Plagiocephaly or flat head

Positional plagiocephaly changes the shape of a baby’s skull without impeding brain growth. An evaluation helps distinguish this common condition from other causes and allows for tailored recommendations for your child.

What is plagiocephaly in babies?

Positional plagiocephaly is an asymmetrical flattening of the skull that occurs when a baby’s head frequently rests on the same area. The back of the head becomes flatter on one side. The ear and forehead on that same side may also appear more prominent¹.

Positional plagiocephaly often develops during the first few months. A baby's skull is malleable, and the baby's head may remain turned to one side for long periods of time.

Two different conditions can alter the shape of the skull. Positional plagiocephaly results from repeated pressure on the same area. Craniosynostosis results from the premature closure of one or more sutures—the joints between the bones of the skull. This second condition is rarer and requires a medical evaluation².

Positional plagiocephaly does not hinder brain growth. However, studies have found more developmental difficulties—especially in motor skills—among babies with positional skull deformities³. This is an association: an association does not prove that the flattening causes a delay. The healthcare professional therefore assesses the baby’s movements and development, in addition to the shape of the baby’s head.

What causes a flat head?

Positional plagiocephaly is caused by prolonged pressure on the same area of the skull, a tendency to turn the head to one side, congenital torticollis, or prematurity¹.

Congenital torticollis can cause the head to remain turned to one side. Therefore, the healthcare professional checks the neck's range of motion when evaluating a flat head.

Preventing flat head syndrome never changes the rules for safe sleep. For every nap, place your baby on his or her back in a firm, flat, and empty space. Instead, vary your baby’s positions when he or she is awake and being watched⁴.

How to recognize plagiocephaly?

Plagiocephaly is primarily characterized by a flattening on one side of the back of the skull. Viewed from above, the head may take on the shape of a parallelogram. The ear and forehead on the flattened side may appear to protrude more.

Certain behaviors also suggest a positioning problem or associated torticollis:

• Your baby always looks to the same side
• His head is often tilted or turned to one side
• He finds it easier to follow toys on one side than on the other
• They don't like being on their tummy
• They have difficulty turning their head to one side

A medical evaluation is recommended if the asymmetry worsens, if a hard lump appears on the skull, or if the shape seems unusual. A clinical examination is usually sufficient to identify a positional deformity. If there is any uncertainty, the healthcare provider may seek the opinion of a specialized team⁵.

When to consult a physiotherapist?

You should seek medical advice as soon as you have concerns about the shape of your baby’s head or if your baby has difficulty turning his or her head. An early evaluation helps identify neck stiffness and begin appropriate treatment, though it does not guarantee a specific rate of correction⁶.

The first few months provide an opportunity to observe movement patterns early on. Recommendations are then tailored to the child’s age, neck mobility, developmental stage, and the degree of asymmetry.

You don't need a referral from your doctor or nurse to see a physical therapist. You can schedule an appointment directly with our pediatric physical therapists.

Imaging is usually not necessary when the clinical examination clearly shows a positional deformity. If the diagnosis remains uncertain, an X-ray or ultrasound of the sutures may be helpful. If these tests still do not provide a definitive answer, the doctor may order a CT scan, a test that produces detailed images of the skull using X-rays⁵.

What does physiotherapy treatment involve?

Treatment begins with an assessment of neck movement, positioning habits, and motor development; the physical therapist then adapts the exercises and waking positions accordingly. If the neck does not turn as well to one side, the physical therapist demonstrates safe ways to encourage movement and vary the points of support⁷.

The physical therapist will go through each exercise with you. He or she will make sure the movement is appropriate for your baby and that you can easily do it again at home.

The duration of treatment varies depending on the severity of the condition. The rate of improvement varies greatly from one baby to another, depending on the baby’s age, the severity of the flattening, and whether or not there is neck stiffness. Your physical therapist measures the asymmetry at each appointment, which gives you a concrete measure of your child’s progress rather than just an average.

What exercises can you do at home?

At home, tummy time should only be done when the baby is awake and being supervised. These activities also help draw the baby’s gaze to both sides and vary the baby’s positions. The physical therapist adjusts the neck movements if the baby has torticollis⁸.

When your baby is awake, place toys and your face on the side your baby looks at less often. Also, alternate which arm you hold your baby in and which side you use to feed them. For every nap, lay your baby on their back in an empty crib, on a firm, flat surface, without any objects that hold their head in a certain position. If they roll over on their own while sleeping, you don’t need to turn them back onto their back⁴.

If you find it difficult to apply these tips or if your baby really dislikes tummy time, our pediatric physiotherapists can show you tricks to make tummy time more enjoyable.

What accessories are recommended?

No pillows or positioners are recommended in the baby’s sleeping area. Repositioning while awake and physical therapy are the first-line options. A helmet may sometimes be considered by a specialized team when the deformity remains moderate or severe⁹.

When putting your baby to sleep, always place your baby on his or her back on a firm, flat surface. Keep the sleeping area clear: no pillows, cushions, bolsters, or positioners should be around the baby⁴.

A helmet may be considered by a specialized team for moderate or severe deformities that persist despite repositioning and physical therapy. It may also be discussed if the baby is seen later with a significant deformity. The decision depends on the baby’s age, the severity of the deformity, its progression, and the family’s preferences⁹.

When a specialized team recommends a helmet, this recommendation complements guidance on positioning and appropriate activities, including supervised tummy time while the baby is awake.

What is the prognosis?

The prognosis for positional plagiocephaly is generally favorable, but the speed and extent of improvement vary. Pressure on the back of the skull often decreases as the baby moves more and changes position more easily¹.

Here's what you can expect:

• With personalized advice: progress is monitored throughout the course of the appointments
• With growth and increased mobility, fitness can gradually improve
• If the asymmetry persists or worsens: a follow-up evaluation may be warranted

The shape of the skull and the baby’s movements are monitored together. Persistent asymmetry does not mean that the brain lacks space to grow.

If you're concerned about the shape of your baby's head, a pediatric physical therapist can evaluate your baby's neck, posture, and development. They will refer you to a doctor if the shape or progression of the condition requires further evaluation.

References

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1. Chrenko R, Plž A, Nedomová B, Kuniaková D. Diagnostic and treatment options for positional plagiocephaly. Wien Med Wochenschr. 2025;175(15-16):394-399. (Back to sections: 1, 2, 3)
2. Mazzola C, Baird LC, Bauer DF, Beier A, Durham S, Klimo P, et al. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline for the Diagnosis of Patients With Positional Plagiocephaly: The Role of Imaging. Neurosurgery. 2016;79(5):E625-E626. (Back to section: 1)
3. Martiniuk AL, Vujovich-Dunn C, Park M, Yu W, Lucas BR. Plagiocephaly and Developmental Delay: A Systematic Review. J Dev Behav Pediatr. 2017;38(1):67-78. (Back to section: 1)
4. Health Canada. Safe Sleep for Every Child. 2024. (Back to sections: 1, 2, 3)
5. Congress of Neurological Surgeons (CNS). 2. The Role of Imaging. 2019. (Back to sections: 1, 2)
6. Blanco-Diaz M, Marcos-Alvarez M, Escobio-Prieto I, De la Fuente-Costa M, Perez-Dominguez B, Pinero-Pinto E, et al. Effectiveness of Conservative Treatments for Positional Plagiocephaly in Infants: A Systematic Review. Children (Basel). 2023;10(7). (Back to section: 1)
7. Ellwood J, Draper-Rodi J, Carnes D. The effectiveness and safety of conservative interventions for positional plagiocephaly and congenital muscular torticollis: a synthesis of systematic reviews and guidance. Chiropr Man Therap. 2020;28(1):31. (Back to section: 1)
8. Congress of Neurological Surgeons (CNS). 4. The Role of Physical Therapy. 2019. (Back to section: 1)
9. Congress of Neurological Surgeons (CNS). 5. The Role of Cranial Molding Orthosis (Helmet) Therapy. 2019. (Back to sections: 1, 2)
10. van Wijk RM, van Vlimmeren LA, Groothuis-Oudshoorn CG, Van der Ploeg CP, Ijzerman MJ, Boere-Boonekamp MM. Helmet therapy in infants with positional skull deformation: a randomized controlled trial. BMJ. 2014;348:g2741. (Back to section: 1)