- See:
- Anterior Subluxation:
- Ligamentous Instability:
- Discussion:
- the flexed view is usually most helpful in detecting ligamentous injury that is not apparent on the neutral view
- determines the integrity of the supporting soft tissues and ligaments, as well as the stability of a known injury
- subluxations may be the sequelae of ligamentous tears w/o frxs;
- this malalignment may only be apparent w/ the dynamic study;
- typically, this view is ordered at 7 to 10 days post injury when C-spine is less tender;
- Flexion View:
- ADI in children should be less than 3.5 mm;
- ADI in adults should be less than 3 mm;
- alignment of cervical canal should assume gentle kyphosis
- interspinous and interlaminar distances should remain symmetric, while facet joint & intervetebral spaces should not widen;
- vertebral body angulation / translation:
- patterns of instability include:
- 1.7 mm or greater of disk widening;
- 3.5 mm of translational displacement (vetebral body subluxation should be no greater than 1 mm as compared to extension view);
- angulation between two adjacent vertebra of 11 deg more than contiguous cervical vertebrae;
- measurements are made from each inferior endplate;
- Extension View:
- mild lordosis;
- as result of compression and rotation compenents, there is unilateral articular pillar frx, subluxation of contralateral facets, disruption of
anterior longitudinal ligament, & mild anterior displacement of the involved body;
- Assessment of RA:
- need to observe any abnormal movements of the C1-C2 level;
- distance > 3mm between anterior arch of Atlas & front of odontoid process is abnormal as is a distance of 3-5 mm between posterior
borders of adjacent subaxial vertebrae;
- Contraindications:
- altered state of consciousness (closed head injury, intoxication, or combativeness);
- documented neurologic deficit;
- inability of patient to flex and extend the neck w/o assistance;
- Technique:
- views are aligned identical to the lateral of the cervical spine
- patient flexes and extends their own neck under the supervision of the requesting physician;
- no manual flexion/extension should be applied;
- adequate amount of flexion is necessary for test to be meaningful;
- support head w/ lead-gloved hand or small pillow after flexed posture is actively achieved by the patient in the supine position