ABSTRACT
Background: Atlas, the first cervical vertebra, has an oblique ligament which bridges the groove for vertebralartery. This ligament may ossify sometimes converting groove into foramen. These foramina are called asponticulus posterior or arcuate foramen of the atlas. The ponticuli can distort vertebral artery. They havetendency to cause vertebra basic insufficiency. During any manipulation of cervical spine, these variations ofatlas should be kept in mind.Objectives: To study the presence of ponticuli, their other features like whether complete or incomplete, unilateralor bilateral, sidedness- right or left.Material and Methods: A total of 50 fully dried adult human atlas were collected from the Department ofAnatomy, Government Medical College, Jammu and from the students of the first year MBBS, Government MedicalCollege, Jammu. Bones were intact and free from osteophytes. The superior surface of posterior arch was observedcarefully in each atlas for presence of ponticulus.Results: In the present study, 50 human atlas vertebrae were observed out of which 4 atlas (8%) had ponticuli. Itwas incomplete in 2 vertebrae (4%) and was complete in 2 atlas vertebrae (4%). It was unilateral in 3 atlasvertebrae (6%) and bilateral in 1 atlas vertebra (2%). 2 ponticuli were on the right side, 1 on left side and 2 werefound on both sides. All were ponticuli posterior except one which was lateral ponticulus.Conclusion: The presence of ponticuli can cause cervical pain and pressurize vertebral artery leading tocerebrovascular accidents. Detailed knowledge about the variations in the cervical region is very helpful toneurosurgeons, orthopaedicians and otolaryngologists to avoid any mishap. Spinal surgeons must be fullyaware about these ponticulus to prevent any complications during surgeries