CERVICAL-SPINE - COMPARISON OF 45-DEGREES AND 55-DEGREES ANTEROPOSTERIOR OBLIQUE RADIOGRAPHIC PROJECTIONS

The orientation of the intervertebral foramina (IVF) at six cervical l evels on transaxial images in 65 magnetic resonance (MR) studies was d etermined to explain variations in size and shape evident on the 45-de grees standard radiographic oblique view. Analysis of MR imaging data showed that substantial variations in the orientation of the cervical IVFs occurred throughout the cervical spine and that a 55-degrees ante roposterior (AP) oblique view with standard radiography probably would lead to better visualization of the lower cervical IVFs. These result s were confirmed with a radiographic and anatomic study of two cadaver ic specimens. In a prospective clinical study of 23 patients, 45-degre es and 55-degrees AP oblique views were compared by measuring the maxi mal transverse diameter of all the cervical IVFs. IVF size was substan tially increased on the 55-degrees AP oblique projection at all lower cervical levels. The 55-degrees AP oblique view of the cervical spine is optimal for evaluating the lower cervical foramina and can be a rou tine alternative to the 45-degrees oblique view in the analysis of all cervical foramina.