Anatomy and Physiology: Biomechanics of Lateral Flexion and Rotation in the Cervical Spine

Introduction

• Presenter: Kevin Tokoff
• Platform: Catalyst University
• Focus: Lateral flexion and rotation in the cervical spine.
• Previous knowledge: Flexion and extension covered in a previous video.

Lateral Flexion (Side Bending)

• Definition: Movement named after the side bending toward; e.g., bending to the right is right side bending.
• Observation: In lateral flexion to the right:
  • Left Side: Becomes longer and more open.
  • Right Side: Becomes shorter and more closed.
• Biomechanics Focus:
  • Focus on lower cervical spine (C2-C3 to C6-C7 segments).
  • Ipsilateral Side (same side): Down-sloping occurs:
    • Superior vertebra moves inferiorly and posteriorly.
    • Facet joints close; intervertebral foramina narrow.
  • Contralateral Side (opposite side): Up-sloping occurs:
    • Superior vertebra moves superiorly and anteriorly.
    • Facet joints open; intervertebral foramina widen.
• Type 2 Mechanics:
  • Lateral flexion and rotation occur in the same direction.

Rotation

• Observation: Individual rotating neck to the right:
  • Ipsilateral Side: Down-sloping occurs, closing facet joints and narrowing foramina.
  • Contralateral Side: Up-sloping occurs, opening facet joints and widening foramina.
• Type 2 Mechanics in Lower Cervical Spine:
  • Rotation and lateral flexion occur in the same direction.

Upper Cervical Spine

• Type 1 Mechanics:
  • Lateral flexion and rotation occur in opposite directions.
  • Example: Right lateral flexion leads to left rotation.

Range of Motion

• Lateral Flexion:
  • Total: 35-40 degrees.
  • Lower cervical spine: 30-35 degrees contribution.
  • Atlanta-occipital joint: 5-degree contribution.
  • Atlanta-axial joint: No contribution.
• Rotation:
  • Total: 65-75 degrees.
  • Lower cervical spine: 30-35 degrees contribution.
  • Atlanta-axial joint (C1-C2): 35-40 degrees contribution.
  • Atlanta-occipital joint: No contribution.

Conclusion

• Understanding the biomechanics of lateral flexion and rotation is crucial for recognizing arthrokinematic movements and the effects on the cervical spine.
• Key Points:
  • Type 2 mechanics in the lower c-spine facilitate same-direction movement of lateral flexion and rotation.
  • Type 1 mechanics in the upper c-spine dictate opposite direction movement.
• Practical Implications:
  • Recognizing side preferences in individuals with radiculopathy or nerve compressions.

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