Wormian Bones
Intrasutural Bones

General Considerations

• Accessory bones within a suture of the skull
• Most often the lambdoid suture
• Usually a normal variant occurring in as many as 80% of Asian population
• Males more frequently affected than females
• Pathological only when greater than 10 in number or large
• A larger, single, centrally located intrasutural bone at the junction of the lambdoid suture and sagittal suture is called the os inca
• They are named after a person (Ole Worm, a Danish anatomist) who described them

Wormian Bones. Multiple accessory bones (white and blue arrows) are seen
within the lambdoid suture of the skull, characteristic of Wormian bones.
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