Ranawat's line is the perpendicular distance between the centre of the sclerotic ring of C2 and a line drawn along the axis of the C1 vertebra.
Normal value is 17 mm in males and 15 mm in females. It is decreased in basilar invagination.
History and etymology
Chitranjan S Ranawat is an American orthopaedic surgeon at the Hospital for Special Surgery in New York City. He described his eponymous line in a paper published in 1979 2.
- 1. Kwong Y, Rao N, Latief K. Craniometric measurements in the assessment of craniovertebral settling: are they still relevant in the age of cross-sectional imaging?. AJR Am J Roentgenol. 2011;196 (4): W421-5. doi:10.2214/AJR.10.5339 - Pubmed citation
- 2. Ranawat CS, O'Leary P, Pellicci P, Tsairis P, Marchisello P, Dorr L. Cervical spine fusion in rheumatoid arthritis. The Journal of bone and joint surgery. American volume. 61 (7): 1003-10. Pubmed