EVALUATING CHAMBERLAIN'S, McGREGOR'S, AND McRAE'S SKULL-BASE LINES USING MULTI DETECTOR COMPUTERISED TOMOGRAPHY

Traditionally the cranio-cervical junction is assessed by lateral cervical spine and base of skull radiographs which however have diagnostic challenges due to the complexity of the anatomy. Modern day Computed Tomography (CT) offers excellent bony detail and its ability to reconstruct the acquired CT data into various imaging planes makes the assessment of the cranio-cervical junction easy and more accurate.

To evaluate the relationship of the odontoid peg of C2 to the standard skull base lines of Chamberlain's, McGregor's and McRae's on computed tomography.

Descriptive cross-sectional study.

Kenyatta National Hospital, Nairobi, between April and September 2010.

The mean position of the odontoid process was 2.6 mm below Chamberlain's line (median 2.7 mm, SD 2.2 mm), 1.0mm (median 0.9 mm, SD 2.1 mm) below McGregor's line and 4.7 mm (median 4.6 mm, SD 1.3 mm) below McRae's line. There was no statistically significant difference in measurements between male and female patients, the different age groups and between CT and standard plain radiograph measurements (p > 0.05).

Anthropometric measurements obtained using CT were lower than those from plain radiographs. There was howeverno statistical significant difference between the two imaging modalities. CT demonstrated far much superior anatomical detail compared to plain radiographs.