Arcuate foramen

In human anatomy, arcuate foramen, also known as ponticulus posticus (Latin for "little posterior bridge"), refers to a bony bridge on the atlas (C1 vertebra) that covers the groove for the vertebral artery. It is a common anatomic variant and estimated to occur in approximately 3-15% of the population. Females are more commonly affected than males.

Pathology
The presence of arcuate foramen is associated with headache, musculoskeletal pain and vertebrobasilar stroke.