What Is Plagiocephaly

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This article will discuss the types, identification and management of plagiocephaly which is sometimes called flat head syndrome. It is pronounced play-jee-oh-kef-ahlee and comes from the Greek words plagio, meaning oblique, and cephalos, meaning head. If you are a parent or carer for a young child and you have some concerns about the shape of your baby’s head then this article is for you.

What Is plagiocephaly?

The human skull is made up of several bones that are joined together by fibrous joints called sutures. These sutures are flexible in newborns to allow the skull to be malleable as it moves along the birth canal. These flexible sutures also allow the head and brain to grow as the infant develops. If these sutures fuse prematurely (craniosynostosis)it can result in difficulties for the developing brain and head. There are two main types of plagiocephaly: positional plagiocephaly and plagiocephaly with craniosynostosis, with the latter being far less common.

The incidence of plagiocephaly has been rising steadily and the peak age of onset is around four months of age.1 This coincides with the advice for parents and carers to place babies on their backs or sides for safe sleeping positions. The significant rise in numbers of plagiocephaly does not affect the development of the brain in the vast majority of cases. However, there are concerns about physical appearance with many parents and carers being concerned about future attractiveness. These concerns may in turn affect attachment, bonding and nurturing from caregivers, and can have exponentially negative effects as the child matures into the teenage years and adulthood.2

Types of plagiocephaly

Positional plagiocephaly

This is the most common type and often presents with flattening of one side of the back of the head. It is due to continuous external pressure and is often caused by staying in a particular position for too long. Other reasons why positional plagiocephaly may develop include:

  • Multiple pregnancies eg twins
  • First birth
  • Premature
  • Instrumentation or assisted birth eg Forceps delivery
  • Lying in a supine position for too long (on your back)
  • Congenital muscular torticollis (tense neck muscles)

Fixed head position due to tight muscles (torticollis) is commonly associated with plagiocephaly but it can be difficult to ascertain which aspect came first. It is thought that whilst most newborns have some head and face asymmetry, up to one in 6 babies will have torticollis. It is important to assess for this at birth because this may limit any efforts to manage the baby with simple strategic repositioning.2

Plagiocephaly with craniosynostosis

This form of plagiocephaly is due to the sutures of the skull fusing prematurely and thankfully this is fairly rare. It affects approximately one in 2000 births and often it is the saggital suture that fuses and results in a long, narrow head. The other main type involves lambdoid suture fusion at the back of the head this is an even rarer occurrence. Here the ear on the affected side is further back than the ear on the unaffected side,  this can distinguish it from simple positional plagiocephaly. Both these types can result in restriction of skull space for the developing brain and thus timely detection is important. Craniosynostosis may result in a ridge being felt near the back of the head and any children with a significantly flattened head or persistent deformity should be referred for specialist assessment at the first suspicion.1

  1. Looman WS and Flannery ABK. Evidence-based care of the child with deformational plagiocephaly, part 1: assessment and diagnosis. 2012, July; 26 (4):242-250
  2. Najaran SP. Infant cranial moulding deformation and sleep position: implications for primary care. J Pediatr Health Care. 1999, July-Aug; 13 (4): 173-7

The incidence of positional plagiocephaly is increasing, and this is thought to be due to healthcare advice to put babies to sleep on their backs.1 Gradual flattening results in altered positions of the ear, the jaw and eye socket and parents and carers may notice that the head is shaped like a parallelogram. 

Plagiocephaly is often diagnosed by careful examination and comparing the position of the jaw, ears and eye sockets on both sides. Assessing the baby from all planes is important as the top of the head may not be level in some cases. Your healthcare provider may measure the diagonal lengths of the skull using an instrument called a caliper which can help detect more subtle differences. Skull xrays are useful to detect whether the sutures have fused (craniosynostosis) and sometimes more detailed imaging is required such MRI and CT to better map out the extent of the problem.2

Management options

It is possible for positional plagiocephaly to naturally correct itself once the child is able to sit up and move independently as this will reduce the continuous pressure. This is, however, dependent on the degree of initial deformity and underlying cause. As with many medical conditions, treatment can be conservative or surgical and again this depends on the severity of the problem at diagnosis.

Conservative options include:

  • Position changes
  • Physiotherapy/Manual therapy
  • Massage therapy
  • Helmet therapy

Helmet therapy/external braces

There are various types of external supports that can be used in the management of plagiocephaly which include specialist headbands, helmets and orthoses. These devices are made of malleable plastic and vary in how they cover and attach to the head. Irrespective of the device, the overall aim is to redistribute pressure whilst promoting growth in flatter areas.

There is no consensus on the ideal timing of helmet therapy or indeed a minimum age. However, helmet therapy should be started before children are able to control head movement. Most doctors would recommend starting helmet treatment before 6 months of age as this is the time when the skull is rapidly

growing. This timing allows for more effective and rapid resolution of any deformity.If conservative treatment is unsuccessful, then helmet therapy can be started from the age of 6 months.3

Surgical treatment

Surgical treatment involves operative correction of the skull deformity and is usually reserved for cases where the skull sutures have fused prematurely (craniosynostosis) or there is severe positional plagiocephaly. Surgical treatment is often followed by helmet therapy for six to twelve months or until the child is 18 months of age to reduce the chances of recurrence.[iv]


Systematic position changes are important to balance forces from repetitive and preferred positions. Any concerns about the shape of a baby's head should be reviewed by a trained healthcare professional to enable appropriate treatment to take place.

Simple observation to see if the baby tends to favour one side more by noting the rotation of the neck.1


The cases of positional plagiocephaly are rising and it is thus important to be aware, of what to look out for and when to seek medical assistance. Most cases can be managed conservatively with simple measures and may not require any additional treatment. There remains some debate about the timing and duration of helmet therapy, but overall there is evidence to show that it is helpful for suitable cases. Surgery is reserved for advanced cases and cases where the skull sutures have fused prematurely. If you are a parent or carer and have concerns then it is important to seek medical advice in a timely fashion as this will allow prompt advice and treatment.

It is also important to consider the psychosocial impact on both the child and carers of untreated deformity as this can have unintended far-reaching effects due to cultural norms and expectations. Families should be supported throughout this period and ongoing or unresolved concerns should be addressed and referred appropriately.

Frequently asked questions

Q: Will a flat head affect my baby’s development?

A: There is no evidence to show that plagiocephaly results in higher levels of developmental or neurological complications.

Q: How is a helmet fitted?

A: Firstly, detailed scans are taken as they allow a 3D reconstruction of the head to be made. Using this head model, a helmet is created to fit snugly around the protruding part of the head whilst also allowing more room around the flatter parts of the head. This design promotes more balanced growth and correction of previously over-pressurised areas.

Q: What can I do to prevent my baby from having a flat head?

A: Regular position changes, seek help early if unsure.

Q: How common is plagiocephaly?

A: Positional plagiocephaly affects up to 48% of infants and the number of cases has increased since safe sleeping advice emerged in the 90%.

Q: Can any baby get plagiocephaly?

A: Plagiocephaly is more common in premature babies, oligohydramnios and deliveries that require birth assistance eg vacuum or forceps.


  1. Argenta LC et al. An increase in infant cranial deformity with supine sleeping position. J Craniofacial Surgery. 1996, Jan; 7 (1): 5-11
  2. Hummel P and Fortado D. Impacting infant head shapes. Adv Neonatal Care. 2005, Dec; 5 (6): 329-40
  3. Jung BK and Yun IS. Diagnosis and treatment of positional plagiocephaly. Archives of Craniofacial Surgery. 2020, April:21 (2): 80-86
  4. Marshall J and Shahzad F. Safe sleep, plagiocephaly, and brachycephaly: assessment, risks, treatment and when to refer. Pediatr Ann. 2020, Oct; 49 (10): e440-47 

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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