Cervical Spine - Oblique

No superimposition of the mandible over the cervical vertebraeRadiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Cervical Spine - Oblique
Area Covered	Vertebrae of the cervical spine, C1 through to C7, as well as the thoracic vertebra T1, the soft tissues of the neck
Pathology shown	Pathologies of the cervical spine,
Radiographic Anatomy	Cervical Spine Radiographic Anatomy
IR Size & Orientation	18cm X 24 cm Portrait
Film / Screen Combination	Regular (CR and DR as recommended by manufacturer)
Bucky / Grid	Moving or Stationary Grid
Filter	No
Exposure	70 kVp 20 mAs
FFD / SID	150 - 180 cm This larger distance helps overcome the OID (object to image receptor distance) to reduce magnification and improve the sharpness of the image.
Central Ray	Directed to the level of C4 Anterior Obliques - 15 degrees caudad (down) Posterior Obliques - 15 degrees cephalad (up)
Collimation	Centre: C4, collimate to the 18 x 24cm film size Shutter A: Open so that the light of the collimated field just includes the top of the ear. Shutter B: Open to include the soft tissue of the neck laterally
Markers	Anterior and Inferior Marker orientation - Posterior Obliques is AP - Anterior Obliques is PA
Shielding	Gonadal (check your department's policy guidelines)
Respiration	Suspended
Positioning	Note that the patient should not be moved or asked to move into position in the case of trauma until the possibility of spinal injury has been ruled out. For Anterior Obliques, Position the patient against the upright bucky in a PA position Angle the patient so that their chest and neck make a 45 degree angle with the bucky Ensure the chin is up slightly to avoid superimposition over the cervical spine For Posterior Obliques, Position the patient in an AP position against the upright bucky Angle the patient so that their back and neck make a 45 degree angle with the bucky Ensure the chin is up slightly to avoid superimposition over the cervical spine
Critique PACEMAN	Positioning Correct obliquity (45 degree rotation of the cervical spine) is evidenced by The intervertebral foramen are open, tear drop shaped and increase in size from C2 down to C7 The pedicles are seen in the anterior half of the vertebral body (see notes below) Correct positioning of the patient's chin is evidenced by No superimposition of the mandible over the cervical vertebrae Correct central ray angulation is evidenced by The intervertebral disc spaces are seen open Area Covered All of the cervical vertebrae are shown, including the intervertebral foramina, as well as T1. Also the anterior soft tissue of the neck and airway are seen. Collimation Centre: C4 Shutter A: Open to show the EAMs superioly and the T1 inferiorly Shutter B: Open to show the soft tissue of the neck anteriorly Exposure Bony trabecular patterns and cortical outlines are sharply defined Soft tissues such as an air filled trachea are visualised
Special Notes	Anterior vs Posterior Obliques Anterior Obliques are generally preferred as, less radiation dose to the thyroid than Posterior Obliques the intervertebral foramina that are demonstrated are those closest to the IR, so therefore, are sharper and less magnified Posterior Obliques demonstrate the intervertebral foramina furthest from the IR Therefore, RAO shows the RIGHT intervertebral foramen LPO shows the RIGHT intervertebral foramen LAO shows the LEFT intervertebral foramen RPO shows the LEFT intervertebral foramen The locaton of pedicles with correct positioning The pedicles are seen in the anterior half of the vertebral body If the patient is "too lateral" the zygopophyseal joints will be visible the pedicles will be seen in the posterior vertebral body If the patient is "too AP" the pedicles are more obscured and are see closer to how they are seen in an AP position, that is, they are positioned equidistant from the vertebral body edges.