Abstract

Background: Atlas, the first cervical vertebra, has an oblique ligament which bridges the groove for vertebral artery. This ligament may ossify sometimes converting groove into foramen. These foramina are called as ponticulus posterior or arcuate foramen of the atlas. The ponticuli can distort vertebral artery. They have tendency to cause vertebra basic insufficiency. During any manipulation of cervical spine, these variations of atlas should be kept in mind. Objectives: To study the presence of ponticuli, their other features like whether complete or incomplete, unilateral or bilateral, sidedness- right or left. Material and Methods: A total of 50 fully dried adult human atlas were collected from the Department of Anatomy, Government Medical College, Jammu and from the students of the first year MBBS, Government Medical College, Jammu. Bones were intact and free from osteophytes. The superior surface of posterior arch was observed carefully 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. It was incomplete in 2 vertebrae (4%) and was complete in 2 atlas vertebrae (4%). It was unilateral in 3 atlas vertebrae (6%) and bilateral in 1 atlas vertebra (2%). 2 ponticuli were on the right side, 1 on left side and 2 were found 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 to cerebrovascular accidents. Detailed knowledge about the variations in the cervical region is very helpful to neurosurgeons, orthopaedicians and otolaryngologists to avoid any mishap. Spinal surgeons must be fully aware about these ponticulus to prevent any complications during surgeries.

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