What are the cracks in your skull called?

Have you ever hit your head so hard that you thought you might have a crack in your skull? Well, that’s not exactly possible, as our skulls are made up of different bones fused together. However, there are certain lines or seams where these bones meet that can sometimes be mistaken for cracks.

The Anatomy of the Skull

Before we dive into what these lines or seams are called, it’s important to understand the anatomy of the skull. Our skulls consist of 22 bones – 8 cranial and 14 facial bones.

The cranial bones form a protective layer around our brain while the facial bones shape our face and provide attachments for muscles responsible for facial movements.

Cranial Bones and Their Junctions

Let’s talk about those mysterious junctions between cranial bones which may appear as cracks at times.

  1. Sagittal Suture: This runs along the midline on top of our head from front to back, separating two parietal bone plates from each other.
  2. Coronal Suture: It is an imaginary line dividing the frontal bone plate (above forehead) from both parietal bone plates.
  3. Lambdoid suture: Located at posterior part separates occipital bone(squamous part) with left and right parietal regions
  4. Squamosal suture: Lateral border extending backwards forms temporal ridge distinguishes superior surface of transient surface(for articulation with mandible).

These sutures play an essential role during fetal development by helping create space for brain growth within the skull.

Fontanelles: Soft Spots on Infant Skull

During childbirth, babies’ heads need some flexibility to get through birth canal.In newborn infants,the above sutures have modification- areas filled with fibrous connective tissue-expanded areas-between developing soft spots and sutures are called fontanelles.

There are two main fontanelles:

  1. Anterior Fontanelle: Located at the top of the head where parietal bones meet with frontal bone, diamond-shaped closure between 12-18 months.
  2. Posterior Fontanelle: This small triangular shaped soft spot closes within a few weeks of birth, and occipital bone meets both parental regions at posterior part

Cracks vs Dura Mater Venous Sinus:

People often mix up these so-called skull “cracks” with a more critical structure: dural venous sinus. These structures usually appear larger than suture lines and run along sides and base of skull’s interior surface,between innermost -Dura mater membrane layer covering our brain & arachnoid layer .

The primary function of this system is to transport deoxygenated blood from veins surrounding brain towards the internal jugular vein in neck for oxygenation via lungs.

It’s not surprising then that these sinuses can become compromised after injury or through medical circumstances such as intracranial hypertension.

However,fortunately,these things happen very rarely,and it’s much more common to witness people mistaking those dural venous sinuses for skull cracks!


While it might be disconcerting to experience certain bumps or bulges forming around cranial junctions,the important thing to remember is that they’re entirely normal! Now you know about sagittal,coronal,lambdoidal,squamosal sutures,you will hopefully have fewer heart palpitations next time your forehead begins puffed up bump due to injury.! Trust us when we say–the crack isn’t there,but those silly-looking seams most certainly are!

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