the angle required to penetrate the intervertebral disc spaces is other than 15 degrees, as visualised on the lateral cervical spine image taken as part of the same examination.Generally, the central ray is approximately 15 degrees up (cephalad). Successful demonstration of the intervertebral disc spaces is largely dependent on correct central ray angulation. Example: If the right pedicle is more towards the midline of the vertebral body (it is rolled under/behind the vertebral body), indicating the patient is rotated so they are looking towards the right side. With correct positioning the pedicles should be equidistant from the vertebral body edges. In an AP view the pedicles are seen laterally in the area between the transverse process and the vertebral body. For example, if the spinous process tip is closer to the left vertebral body edge, then the patient's neck is rotated so they are looking towards the right side. As the head is rotated in a particular direction, the spinous process tip will move in the opposite direction. When the spinous processes are not seen in the midline of the vertebral bodies this usually indicates rotation of that part of the cervical spine. Soft tissues such as an air filled trachea are visualised.Bony trabecular patterns and cortical outlines are sharply defined.Shutter B: Open to include the soft tissue of the neck laterally.Shutter A: Open to include the base of skull superiorly and approximately T2 inferiorly.Cervical vertebrae C3 through to C7 are visualised.The intervertebral disc spaces are seen open (see notes below).Correct central ray angulation is evidenced by.The superimposition of the mandible over the base of the skull (see notes below).Correct alignment of the occlusal plane and the base of skull is evidenced by.The mandibular angles are equidistant from the cervical spine.The pedicles are equidistant from the vertebral body edges (see notes below).The spinous processes are seen in the midline of the vertebral bodies (see notes below).Position the interpupillary line so that it is parallel to the IR.Position the IR patient so that it is either in the table bucky, or is on the barouche posterior to the cervical spine.Raise the chin slighlty, so that the line of the occlusal plane superimposes the base of the skull.Position the interpupillary line so that it is parallel to the IR (in an erect patient, this will also be parallel to the floor).Position the midsagittal plane so that it is perpendicular to the IR.(This allows the patient to rest their back against the bucky, and may help to minimise patient movement) Using the upright bucky, position the patient in an AP position.Take care to ensure no rotation of either the head, neck or torso. Only request the patient move into position if the possibility of spinal injury has been ruled out.Ensure the removal of artefacts that may superimpose the anatomy of interest.Gonadal (check your department's policy guidelines) Shutter B: Open to include the soft tissue of the neck laterally The light will appear to bend around due to the central ray being angled cephalad Shutter A: Open so that the light of the collimated field just includes the top of the ear. (to match the lordotic curve of the cervical spine, to penetrate the intervertebral disc spaces)Ĭentre: C4, collimate to the 18 x 24cm film size (CR and DR as recommended by manufacturer)ĭirected to the level of C4, which is approximately the level of the angle of the mandibleġ5 degrees cephalad. Some pathologies of the cervical vertebrae C3 through to C7 The cervical vertebrae from C3 down to approximately T2
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