Accessory intraparietal suture

Case contributed by Mauricio Macagnan
Diagnosis certain


Neonate with mild head trauma. No apparent alteration in consciousness.

Patient Data

Age: 4 months
Gender: Male

Accessory intraparietal suture also known as subsagittal suture, identified in both parietal bones. Suspected small hairline fracture emanating posteriorly from the right intraparietal suture. The brain shows normal attenuation, with no evidence of intracranial hemorrhage.

Annotated image

The reconstruction demonstrates the sutures of the skull.

The white arrows demonstrate the usually identifiable sutures and the red arrow locates the accessory intraparietal suture.

There is a small hairline fracture originating from the right intraparietal suture, coursing posteriorly.

Case Discussion

Partial or complete division of parietal bones resulting in abnormal cranial sutures is a rare entity and may result in difficulty of differentiation from fractures in small children with head trauma.

Usually, non-depressed simple skull fractures are radiolucent, with non-sclerotic borders. In contrast, accessory sutures usually present with sclerotic borders, similar to large skull capillary sutures. Bilaterality of accessory sutures is frequent and symmetrical, especially in the parietal bones. However, skull fractures may also be bilateral but almost always associated with high-impact lesions and therefore often show marked depression and asymmetry, as well as intracranial lesions and soft tissue injury.

It is important to know the normal anatomy, development and chronology of sutural closure for the evaluation of the small child with head trauma and suspected fracture.
Accessory sutures can be differentiated from fractures in most cases by observing their characteristics, such as bilaterality, symmetry, diastasis, and presence of soft tissue injury.

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