Table 1.
Measured parameters of videofluoroscopy (VF) views/motions.
| Anatomical/Biomechanical Parameter (View) | Vertebral Level | VF motion Examination/View Details | Measurement Details | Expected Normal Values |
|---|---|---|---|---|
| Lateral overhang (AP) | C1-2 | A-P open mouth, R and L lateral flexion | Maximum difference in lateral translation (in mm) of the lateral margin of the lateral mass of C1 relative to the lateral margin of the superior articular facet of C2, between sides | 2 mm or less overhang difference between sides |
| Peri-odontoid space symmetry (AP) | C1-2 | A-P open mouth, R and L lateral flexion | Bilateral symmetry of gap between dens of C2 and medial margin of lateral mass of C1, observed at extreme R and L flexion | Symmetrical gap maintained |
| Translation (lat) | C2-7 | Lateral flexion-extension | Maximum anterior (in flexion) or posterior (in extension) translation of vertebral body relative to adjacent inferior vertebra, measured at posterior vertebral body line | 2 mm or less anterior or posterior translation |
| Intervertebral angulation (lat) | C2-7 | Lateral flexion-extension | Angle between adjacent posterior vertebral body lines in maximum flexion | 10 degrees or less |
| SP engagement (lat) | C2-7 | Lateral flexion-extension | Degree of synchronous movement between adjacent spinous processes during flexion from neutral | Inter-spinous process distance increases commensurately with flexion |
| SP coupled movement (AP) | C2-7 | AP c-spine R and L lateral flexion | Degree of coupled spinous process rotation with ipsilateral flexion | Spinous process rotates during lateral flexion |
| Facet gapping (AP) | C2-7 | AP c-spine R and L lateral flexion | Degree of separation at facet during maximal lateral flexion | No appreciable gapping at maximum lateral flexion |
| Facet gapping (obl) | C2-7 | R and L oblique c-spine flexion-extension | Degree of separation at facet during maximal forward flexion | No appreciable gapping at maximum forward flexion |
| Facet symmetry (obl) | C2-7 | R and L oblique c-spine flexion-extension | Degree of symmetrical movement at facets during flexion and extension, comparing right and left | Movement and degree of gapping is symmetrical between sides |
Abbreviations: AP = anterior to posterior view, lat = lateral view, obl = oblique view, mm = millimeters, R and L = right and left, SP = spinous process, c-spine = cervical spine.