AP and Pa oblique C spine

What is the primary warning for trauma patients undergoing cervical spine imaging?

Do not remove the cervical collar or move the head and neck until authorized by a physician. Always protect the cervical spine until injury is ruled out.

What are the clinical indications for cervical spine oblique projections?

Pathology involving the cervical spine, adjacent soft tissues, and stenosis of the intervertebral foramina. Obliques are commonly used to evaluate the intervertebral foramina.

Why are anterior oblique projections preferred over posterior oblique projections?

They reduce radiation dose to the thyroid gland. RAO and LAO provide the same information while exposing the thyroid to less radiation.

What SID is recommended for cervical spine oblique projections?

40–72 inches (100–180 cm), with a longer SID preferred. A longer SID reduces magnification and improves image quality.

What kVp range is recommended for cervical spine oblique projections?

70–85 kVp. Standard cervical spine exposure range.

What is the preferred patient position for cervical spine oblique imaging?

Erect (sitting or standing). Recumbent positioning may be used if necessary.

What CR angle is used for anterior oblique cervical spine projections (RAO/LAO)?

15°–20° caudad to C4. Anterior obliques always use a caudad angle.

What anatomy is demonstrated on anterior oblique cervical spine projections?

Intervertebral foramina and pedicles on the side closest to the IR. Remember: Anterior = Same Side.

What anatomy is demonstrated on posterior oblique cervical spine projections?

Intervertebral foramina and pedicles on the side farthest from the IR. Remember: Posterior = Opposite Side.

What indicates proper positioning on cervical spine oblique projections?

Intervertebral foramina and disk spaces are open and uniform in size and shape. Open foramina indicate correct rotation and angulation.

What are the respiration instructions for cervical spine oblique imaging?

Suspend respiration. Prevents motion blur.

What do obscured intervertebral foramina indicate?

Under-rotation. The patient was not rotated enough.

What does visualization of the zygapophyseal joints indicate on cervical obliques?

Over-rotation. The patient was rotated too much.

Why is the chin protracted during cervical spine oblique positioning?

To prevent the mandible from superimposing the cervical vertebrae. Moves the jaw away from the anatomy of interest.

Why is a protractor or angle gauge used during cervical spine oblique positioning?

To ensure a true 45° oblique position. Correct rotation is critical for opening the foramina.

What happens if the skull and neck are excessively extended?

The base of the skull superimposes the posterior arch of C1. Too much extension hides upper cervical anatomy.

What CR angle is used for posterior oblique cervical spine projections (RPO/LPO)?

15°–20° cephalad to C4. Posterior obliques always use a cephalad angle.

How should a patient be positioned for cervical spine oblique projections?

Rotate the body and head 45°. Protract the chin. Elevate the chin until the acanthiomeatal line (AML) is parallel to the floor. These steps prevent mandibular superimposition and properly open the intervertebral foramina.