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Chamberlain’s line

Chamberlain line is a line joining the back of hard palate with the opisthion on a lateral view of the craniocervical junction.

Less than 3 mm or half of dens should be above this line, with 6 mm being definitely pathologic. Seldom used because the opisthion is often hard to see on plain film and may also be invaginated. On CT 1) and MRI 2) the normal odontoid tip is 1.4 mm (± 2.4) below the line


It helps to recognise basilar invagination which is said to be present if the tip of the dens is >3 mm above this line.

McGregor developed a modification of the Chamberlain line for when the opisthion could not be identified on plain radiographs.

see McGregor's line.

Cronin CG, Lohan DG, Mhuircheartigh JN, Meehan CP, Murphy J, Roche C. CT evaluation of Chamberlain's, McGregor's, and McRae's skull-base lines. Clin Radiol. 2009; 64:64–69
Cronin CG, Lohan DG, Mhuircheartigh JN, Meehan CP, Murphy JM, Roche C. MRI evaluation and measurement of the normal odontoid peg position. Clin Radiol. 2007; 62:897–903
chamberlain_s_line.txt · Last modified: 2019/10/14 18:39 by administrador