Which vertebrae are responsible for rotation of the neck?

Cervical Spine Rotation: Anatomical and Clinical Considerations

The atlantoaxial joint (C1-C2) is primarily responsible for rotation of the neck, providing approximately 50% of total cervical rotation. 1, 2

Anatomical Basis of Cervical Rotation

Primary Rotational Segments

• C1-C2 (Atlantoaxial joint): Contributes 40-50% of total cervical rotation 2
• Remaining cervical segments: Each contributes smaller amounts to total rotation
  • C0-C1: ~1 degree
  • C2-C3: ~3 degrees
  • C3-C4: ~6.5 degrees
  • C4-C5: ~6.8 degrees
  • C5-C6: ~6.9 degrees
  • C6-C7: ~5.4 degrees
  • C7-T1: ~2.1 degrees

Anatomical Features Enabling Rotation

• The atlantoaxial joint has a unique structure that facilitates rotation:
  • The odontoid process (dens) of C2 acts as a pivot point
  • The atlas (C1) rotates around this pivot
  • The transverse ligament holds the dens against the anterior arch of C1
  • The unciform processes guide rotation 2

Clinical Significance

Injury Patterns

• Injuries to the atlantoaxial complex can severely compromise cervical rotation
• Cervical spine injuries account for 10-17% of all trampoline-related injuries 3
• Atlanto-axial rotatory displacement can cause childhood torticollis and chronic neck pain after rear-end collisions 4

Imaging Considerations

• CT is superior to plain radiographs for identifying cervical spine fractures (98% vs 36% sensitivity) 5
• MRI is recommended for soft tissue injury assessment, identifying ligamentous damage in 5-24% of blunt trauma patients with negative CT 5
• Normal rotation in asymptomatic adults averages 79 degrees (range: 74-81 degrees) 6

Airway Management Implications

• When tracheal intubation is required in patients with suspected cervical spine injury:
  • Videolaryngoscopy is preferred over direct laryngoscopy 3
  • Jaw thrust is recommended over head tilt with chin lift to maintain the airway while minimizing cervical movement 3
  • Videolaryngoscopy produces less cervical spine movement than direct laryngoscopy with a Macintosh blade 3

Assessment of Rotational Function

• CT scans can quantify rotation by measuring:
  • Rotation angle between C1 and C2
  • Contact surface loss between articular facets 6
• MRI and CT are equally effective in assessing C2 malrotation 4
• Spinous process deviation on plain radiographs can estimate rotation (approximately 1.62 degrees per mm of deviation) 4

Management Considerations

• Cervical collars:

  • Rigid collars provide better stability than soft collars for limiting flexion/extension and rotation 3
  • However, prolonged use beyond 48-72 hours is associated with complications including pressure ulcers and increased intracranial pressure 5
  • Soft collars have limited effectiveness in restricting cervical spine movement 3

• For suspected atlantoaxial injuries:

  • Prompt recognition and treatment are essential due to potential for spinal cord compromise 1
  • CT is the preferred initial imaging modality 5
  • MRI should be considered when neurological deficits are present 5

Understanding the critical role of the atlantoaxial joint in cervical rotation is essential for proper assessment and management of neck injuries and conditions affecting rotational mobility.