Cervical spine (AP oblique view)
The AP oblique cervical spine projections are supplementary views to the standard AP, odontoid and lateral c-spine series. It can be taken either as an anterior oblique or posterior oblique projection.
- patient is standing erect with either the left or right posterior side closer to the image receptor
- the thorax and cervical spine is at 45 degrees to the image receptor
- the face is in a lateral position with the interpupillary line perpendicular to the image receptor
- anteroposterior oblique
- C4 at or just above the level of the hyoid bone
- 15° cranial tilt of the central ray
- superiorly to include all of C1/base of skull and inferiorly to include to at least T1 (EAM to sternal notch)
- laterally to include the entire cervical spine including the spinous processes and the anterior soft tissue of the neck
- 18 cm x 24 cm
Image technical evaluation
- all of the cervical spine anatomy should be included from C1-T1
- patient’s head should be in a lateral position to prevent mandibular superimposition over the vertebral bodies of the c-spine
- intervertebral foramina of the side positioned further from the image receptor should be demonstrated open
Make sure that any removable artefacts such as earrings, glasses or metal dentures are removed to avoid obscuring the anatomy of interest.
Using a larger source to image distance will decrease magnification of the image and improves acuity 1
Remember that for AP Oblique cervical spine positioning the patient will either be in an RPO or LPO position and that posterior obliques demonstrate the foramina opposite to your patient positioning 3
For example, an LPO will demonstrate the right foramina
Correcting rotational errors
To demonstrate the intervertebral foramen of the c-spine open, it is necessary to achieve correct rotation of the vertebral column, usually at 45 degrees.
If under rotated, the foramina will be narrowed and a sternoclavicular joint would be superimposed over the vertebral column 2.
Over rotation of more than 45 degrees would cause one pedicle to be foreshortened while the other pedicle aligns to the midline of the vertebral bodies 1.
- 1. Frank E, Long B, Smith B, Merrill V. Merrill's atlas of radiographic positioning & procedures. 12th ed. Jeanne Olson;.
- 2. McQuillen-Martensen KMcQuillen-Martensen K. Radiographic image analysis workbook. 2nd ed. St. Louis, Mo.: Elsevier Saunders; 2006.
- 3. Pate D. Obliques: Which Foramen Are We Looking At? [Internet]. Dynamicchiropractic.com. 2017 [cited 20 February 2017]. Available from: http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=31483