Cervical Myelopathy in Rheumatoid Arthritis

Figure 1

Basilar invagination is present when the odontoid tip is >6 mm above the Chamberlain’s line; above McRae’s line; >8 mm above McGregor’s line in males and >9.7 mm above this line in females; or when the Redlund-Johnell distance is <34 mm in males and <29 mm in females.