Abstract:
Ponticuli in the atlas vertebra are bony spurs seen frequently from the anterior and posterior
margins of the groove for the vertebral artery, which may convert the groove into a foramen.1
This foramen is known as foramen arcuale. The foramen arcuale is infrequently found and is
potentially a clinically/surgically significant anatomical variation of the atlas. When present, the
vertebral artery travels through this bony ring after exiting