An Anatomical Study of the Morphometric Differences between Complete Arcuate Foramina and Ipsilateral Foramina Transversaria in Human Atlas Vertebrae: Could these Be Responsible for Vaso-occlusive Symptoms?

• Published in: National journal of clinical anatomy (Online) Vol. 8; no. 3; pp. 106 - 111
• Main Authors: Lalit, Monika, Mahajan, Anupama, Piplani, Sanjay, Kullar, Jagdev S.
• Format: Journal Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 01-07-2019
• Subjects: arcuate foramen; area; foramen transversarium; ponticuli; vertebral artery
• ISSN: 2277-4025; 2321-2780
• DOI: 10.1055/s-0039-1697550

Abstract
Background and Aims Arcuate foramina (AF), the atlas bridges formed by a delicate bony spicule over the posterior arch of atlas, have been implicated in the compression of the vertebral artery during extreme rotation of head and neck movements. Reduction in the size of arcuate foramina as compared with foramen transversarium (FT) is also an important cause for the compression of vertebral artery. Aim of the present study was to determine the morphometric differences between complete AF and ipsilateral foramina transversaria.
Materials and Methods Eighty dry adult human atlas vertebrae were obtained in the Department of Anatomy, Government Medical College and Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, Punjab, India. Measurements were taken of the maximum dimensions of AF and ipsilateral FT and cross-sectional area was also calculated.
Results The following results were obtained.
The AF were seen in total 11 (13.75%) vertebrae, 3 (3.75%) on the right side, 6 (7.5%) on left side, and 2 (2.5%) bilateral.
• The mean ventrodorsal (AFL) and superoinferior (AFH) diameter of AF was 8.79 mm and 5.98 mm, and 8.11 mm and 5.54 mm on the right and left sides, respectively, and the difference was found to be highly significant.
• The mean ventrodorsal (FTL) and mediolateral (FTW) diameter of the FT 8.19 mm and 6.56 mm, and 7.31 mm and 6.86 mm on the right and left sides, respectively, with significant difference on the right side.
• The mean cross-sectional area of AF was 41.32 mm2 and 35.38 mm2, and FT was 42.53 mm2 and 39.71 mm2 on the right and left sides, respectively, and AF has smaller area than ipsilateral FT.
Conclusions Knowledge about the dimensions and cross-sectional area of the AF and ipsilateral foramina transversaria of the atlas vertebra can improve the success rate of surgeries, thus preventing damage to the adjoining vital structures.