The skull of an infant or young child is made up of bony plates that allow for growth. The borders where these plates come together are called sutures or suture lines.

In an infant only a few minutes old, the pressure from delivery may compress the head. This makes the bony plates overlap at the sutures and creates a small ridge. This is normal in newborns. In the next few days, the baby's head expands. The overlap disappears and the edges of the bony plates meet edge-to-edge. This is the normal position.

Diseases or conditions that cause an abnormal increase in the pressure within the head can cause the sutures to spread apart. These separated sutures can be a sign of pressure within the skull (increased intracranial pressure).

Separated sutures may be associated with bulging fontanelles. If intracranial pressure is increased a lot, there may be large veins over the scalp.

The problem may be caused by:

• Arnold-Chiari malformation
• Battered child syndrome
• Bleeding inside the brain (intraventricular hemorrhage)
• Brain tumor
• Certain vitamin deficiencies
• Dandy-Walker malformation
• Down syndrome
• Hydrocephalus
• Infections that are present at birth (congenital infections)
• Lead poisoning
• Meningitis
• Subdural hematoma or subdural effusion
• Underactive thyroid gland (hypothyroidism)

Contact your health care provider if your child has:

• Separated sutures, bulging fontanelles, or very obvious scalp veins
• Redness, swelling, or discharge from the area of the sutures

The provider will perform a physical exam. This will include examining the fontanelles and scalp veins and feeling (palpating) the sutures to find out how far they are separated.

The provider will ask questions about the child's medical history and symptoms, including:

• Does the child have other symptoms (such as abnormal head circumference)?
• When did you first notice the separated sutures?
• Does it seem to be getting worse?
• Is the child otherwise well? (For example, are eating and activity patterns normal?)

The following tests may be performed:

• MRI of the head
• CT scan of the head
• Ultrasound of the head
• Infectious disease work-up, including blood cultures and possible spinal tap
• Metabolic work-up, such as blood tests to look at electrolyte levels
• Standard eye exam

Although your provider keeps records from routine checkups, you might find it helpful to keep your own records of your child's development. Bring these records to your provider's attention if you notice anything unusual.

Separation of the sutures

Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW. Head and neck. In: Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW, eds. Seidel's Guide to Physical Examination. 10th ed. St Louis, MO: Elsevier; 2023:chap 11.

Goyal NK. The newborn infant. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 113.

Rosenberg GA. Brain edema and disorders of cerebrospinal fluid circulation. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 88.

Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.