AP Cervical Spine X-Ray with Open mouth

Open Mouth - Cervical X-ray

X-ray examination of cervical spine projecting C1 and C2 with the patient in open mouth. When performing an x-ray of Cervical spine (AP) and the patient has a neck trauma don't attempt to move the head and neck without consulting first with a physician who reads the previous horizontal beam lateral radiograph of the patient.

Pathology Demonstrated and Exposure Factors

Fractures of C1 and C2 and adjacent soft tissues
Odontoid and Jeffeson Fractures will be demonstrated
Film size is 18x24 cm or 8 x 10 inches
Use of Grid either stationary of moving grid

Patient Position:

Patient is in supine or erect and put arm by sides
Head is in table surface, and provide immobilization if needed.

Part Position AP Cervical Spine Open Mouth

Patient in open mouth demonstrating C1 to C2
Align midsagittal plane to Central Ray and midline of x-ray table
Open mouth and adjust patient head, a line from lower margin of upper incisors to the base of the skull or mastoid tip is perpendicular to the image receptor and x-ray table or align Central Ray accordingly.
Be sure that no rotation of patients head or thorax exist.
Ensure that the patient mouth is wide open during exposure. note: Do this at last step and make it quick, because patient will be difficult in this position.

Central Ray, Collimation and Respiration:

Central ray is directed to the center of mouth and perpendicular to image receptor or cassette.
SID use is 40 inches or 100 cm
Collimate to the 4 side of area to be image, approximately 4 x 4 inches or 10 x 10 cm
Suspend during exposure to minimize patient motion.

Important: If patient is instructed to open the mouth, only the lower jaw moves and keep the tongue in the lower jaw to prevent superimposition of tongue's shadow to the atlas and axis.
If the dens, cannot be demonstrated in this position you may use Fuchs method and Judd method.

Radiographic Criteria

Structure Shown and Position

Cervical Spine: Open Mouth - C1 to C2

Patient in open mouth the Odontoid process (Dens) and vertibral body of C2, the lateral masses of C1 and zygopopseal joints between C1 and C2 should be clearly demonstrated.
Proper flexion or extension of the neck will superimpose the lower margin of the upper incisors with base of the skull. Neither teeth are sperimposed on the upper dens, when making reposition on patient hyperextending the neck or angle the central ray slightly cephalic.

If the skull base is superimposing the upper dens, reposition the patient by slightly hyperflexing the neck or angle central ray slightly caudad it will project about 1inch or 2.5 cm for every 5 degree of caudal angulation.

No Rotation: Equal distance from lateral masses and or transverse process of C1 to condyles of mandible, and by center alignment of spinous process of C2. Rotation can be imitate pathology by causing unequal spaces between lateral masses and dens.

Collimation and Central Ray:

The dens must be center of collimated field of approximately 4 x 4 inches or 10 x 10 cm.

Criteria for Exposure Technique

Both bone and soft tissue densities are demonstrated if optimal exposure have used.
Clear or sharp bony margins and trabecular markings which is an indication of no motion.