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Cervical flexion, extension, protrusion, and retraction. A radiographic segmental analysis
N R Ordway1, R J Seymour, R G Donelson
1Department of Orthopedic Surgery, SUNY Health Science Center at Syracuse, USA. ordwayn@hscsyr.edu
Spine
|February 20, 1999
Summary
Cervical spine protrusion and retraction movements involve greater motion at the occiput-C1 and C1-C2 segments compared to full flexion or extension. These findings may explain cervical symptoms related to specific movements.
Area of Science:
- Biomechanics of the cervical spine
- Radiographic analysis of spinal motion
Background:
- Clinical relevance of cervical protrusion and retraction in symptomatic individuals is increasingly recognized.
- Limited quantitative data exists on the biomechanics of cervical protrusion and retraction.
Purpose of the Study:
- To quantitatively assess the contribution of each cervical spine segment to end-range sagittal movements.
- To analyze four distinct sagittal positions: full-length flexion, full-length extension, protrusion, and retraction.
Main Methods:
- Lateral radiographic analysis of the cervical spine was conducted on 20 asymptomatic volunteers.
- Measurements were taken in neutral, full flexion, full extension, protrusion, and retraction positions.
- Angular measurements and range of motion were calculated for segments from occiput to C7.
Main Results:
- Cervical retraction involves lower cervical extension and upper cervical flexion.
- Cervical protrusion involves lower cervical flexion and upper cervical extension.
- Occiput-C1 and C1-C2 segments demonstrated a greater range of motion in protrusion and retraction compared to full flexion/extension.
Conclusions:
- Protrusion and retraction yield greater motion at upper cervical segments (Occ-C1, C1-C2) than full flexion or extension.
- The specific positions of lower cervical segments during flexion, extension, protrusion, and retraction may correlate with reported cervical symptoms.