What are the key findings to look for in a lateral neck x-ray (lateral neck radiograph)?

Key Findings to Look for in a Lateral Neck X-ray

The lateral neck radiograph is a valuable imaging tool that can detect various pathologies when properly evaluated for specific anatomical structures, soft tissue relationships, and abnormalities.

Essential Anatomical Structures to Evaluate

• Cervical vertebrae: Assess alignment from the craniocervical junction (occipito-atlantal articulation) to the cervicothoracic junction, looking for fractures, subluxations, or dislocations 1
• Prevertebral soft tissue thickness: Normal measurements vary by age - approximately 6.2mm in infants to 3.7mm at C3 level in adults, and 9.2mm in preschoolers to 12.1mm at C6 level in adults 2
• Airway patency: Evaluate the air column for narrowing, displacement, or obstruction 1
• Soft tissue spaces: Assess retropharyngeal and retrotracheal spaces for widening, which may indicate infection, hemorrhage, or edema 1, 3
• Cervical lordosis: Evaluate for loss of normal curvature, which may indicate muscle spasm or injury 4

Key Pathological Findings

Trauma

• Fractures and dislocations: Look for disruption in vertebral body alignment, widened interspinous distances, or obvious fracture lines 1
• Prevertebral soft tissue swelling: May indicate hemorrhage from cervical spine injury 1
• Alignment abnormalities: Check for straightening of normal cervical lordosis, which may indicate muscle spasm from injury 1

Infection

• Retropharyngeal abscess: Look for widened prevertebral space (>7mm at C2 or >14mm at C6 in adults), though be aware that high nasopharyngeal abscesses may not be visible on lateral films 3, 5
• Epiglottitis: Observe for thickened, edematous epiglottis ("thumb sign") 1
• Soft tissue gas: May indicate necrotizing infection 1

Foreign Bodies

• Radiopaque densities: Direct visualization of foreign objects in the aerodigestive tract 4
• Abnormal air column lucency: Indirect sign of foreign body presence 4
• Increased prevertebral soft tissue thickness: Particularly at C6 level (>20mm warrants attention) 4

Technical Considerations

• Adequate visualization: The lateral view must include from the base of skull to the cervicothoracic junction (C7-T1) 1
• Proper positioning: Upright positioning provides functional information about axial loading 6
• Supplementary views: While lateral view is most important, additional views (AP, odontoid) may be needed for complete evaluation 1, 7

Limitations and Pitfalls

• Sensitivity limitations: The lateral view alone misses approximately 15% of cervical spine injuries 1
• Technical inadequacy: 10-20% of missed injuries result from misinterpretation of suboptimal radiographs 1
• Cervicothoracic junction: This area is difficult to visualize (visible in only 51% of cases) yet contains up to 60% of cervical injuries 1
• False negatives: Normal lateral neck X-rays do not exclude high nasopharyngeal abscesses or early infections 5
• Age considerations: Normal variants in children <8 years (pseudosubluxation of C2-C3, absence of lordosis, widened atlantodental interval) can complicate interpretation 8

When to Consider Advanced Imaging

• CT scan: When radiographs show abnormal or ambiguous findings, or when high clinical suspicion exists despite normal radiographs 1
• MRI: When neurological deficits are present, or when ligamentous injury is suspected 1, 8
• CT myelography: When MRI is contraindicated or inconclusive 1