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XRAY
HeadDemonstration data

Skull X-Ray

Plain skull radiography has a limited and declining role because CT is superior for both intracranial injury and fracture detection. It retains value for assessing bony lesions, certain craniofacial abnormalities, suspected non-accidental injury as part of a skeletal survey, foreign bodies and shunt/device surveys. Interpretation requires familiarity with normal sutures and vascular grooves, which are commonly mistaken for fractures.

Indications

  • Suspected metabolic or destructive bone lesions of the calvarium (myeloma, metastasis, Paget disease)
  • Skeletal survey for suspected non-accidental injury in children
  • Assessment of craniofacial dysostoses and congenital anomalies
  • Localisation of radiopaque foreign bodies
  • Survey of ventriculoperitoneal shunt tubing and cranial hardware
  • Suspected skull fracture only where CT is unavailable (CT strongly preferred)
  • Evaluation of the sella turcica and skull base in selected pituitary or endocrine cases

Contraindications & Cautions

  • No absolute contraindications
  • CT is preferred for head trauma; do not use skull radiographs to exclude intracranial injury
  • Pregnancy: negligible fetal dose but justify and shield
  • Low radiation dose (~0.07 mSv) but includes radiosensitive lens of the eye - collimate and apply ALARA
  • Avoid in acute head injury where CT is indicated by clinical decision rules

Patient Preparation

  • Remove hairpins, earrings, dentures, hearing aids and other radiopaque items
  • No fasting or sedation routinely required (sedation occasionally needed in young children)
  • Position the head accurately using the orbitomeatal baseline for standard projections
  • Explain the breath-hold and need for immobility to avoid motion blur
  • Immobilise infants appropriately for a skeletal survey
  • Confirm pregnancy status where relevant

Technique & Parameters

  • Standard projections: PA (or AP) and lateral views
  • Towne (AP axial) projection demonstrates the occipital bone and foramen magnum
  • Waters (occipitomental) projection demonstrates the facial bones and paranasal sinuses
  • 70-80 kVp with a grid; fine detail with the head immobilised
  • Both lateral sides may be imaged in a skeletal survey; symmetrical positioning is essential
  • Submentovertical and other specialised views occasionally used for the skull base
  • CT with bone windows is the definitive study for fractures and skull-base assessment

Systematic Review

  • Assess adequacy and positioning symmetry
  • Trace the calvarial cortical tables (inner and outer) for lucency or destruction
  • Identify normal sutures (coronal, sagittal, lambdoid) and vascular grooves to avoid mistaking them for fractures
  • Evaluate the skull base, sella turcica size and cortex, and petrous bones
  • Assess the diploic space and any focal lytic or sclerotic lesion
  • Check for pineal or other physiological calcification and any midline shift of calcified structures
  • Review facial bones and sinuses on Waters view; occiput on Towne view
  • Look for foreign bodies, air (pneumocephalus) and device/shunt positions

Key Findings & Significance

  • A lucent line that is sharp, non-branching and does not follow a sutural course suggests a fracture, while branching, corticated lines are usually vascular grooves or sutures
  • Multiple well-defined 'punched-out' lucencies suggest multiple myeloma or metastases
  • Mixed lytic and sclerotic thickened calvarium with a 'cotton wool' appearance suggests Paget disease
  • A 'hair-on-end' diploic appearance suggests chronic haemolytic anaemia
  • Enlargement or erosion of the sella turcica suggests a pituitary mass
  • Widened sutures (sutural diastasis) in a child may indicate raised intracranial pressure
  • A depressed fragment produces a double density of overlapping bone
  • Displaced radiopaque foreign body localised on orthogonal views

Differential Considerations

  • Lucent calvarial lesion: metastasis, myeloma, epidermoid, eosinophilic granuloma, arachnoid granulation, surgical defect
  • Sclerotic calvarial lesion: osteoma, fibrous dysplasia, Paget disease, sclerotic metastasis, meningioma-related hyperostosis
  • Lucent line: fracture, suture, vascular groove, venous lakes
  • Generalised calvarial thickening: Paget disease, chronic anaemia, acromegaly, fibrous dysplasia, phenytoin therapy
  • Enlarged sella: pituitary adenoma, empty sella, raised intracranial pressure, craniopharyngioma
  • Intracranial calcification: physiological (pineal, choroid plexus), tumour, old infection, vascular
  • Multiple wormian bones: osteogenesis imperfecta, cleidocranial dysostosis, hypothyroidism

Pearls & Pitfalls

  • Do not use skull radiographs to exclude intracranial haemorrhage - CT is required; a normal skull film does not exclude significant brain injury
  • Sutures and vascular grooves are the commonest mimics of fracture; fractures are lucent, sharp, straight and non-branching without corticated margins
  • A fracture crossing the middle meningeal artery groove raises concern for extradural haematoma - proceed to CT
  • Arachnoid granulations and venous lakes are well-corticated lucencies that should not be called lytic lesions
  • In suspected non-accidental injury, correlate with the full skeletal survey and clinical context
  • The lens of the eye is radiosensitive - collimate carefully
  • Correlate any suspected fracture or lesion with cross-sectional imaging

Structured Report

  • State projections obtained and adequacy
  • Report calvarial integrity, sutures, skull base and sella
  • Describe any lucent or sclerotic lesion with size, margin and distribution
  • Distinguish fracture from vascular groove/suture and state the reasoning
  • Note foreign bodies, devices, shunt tubing and calcifications
  • Impression: summarise findings and recommend CT for suspected fracture, intracranial injury or lesion characterisation

References

  • ACR Appropriateness Criteria: Head Trauma
  • Royal College of Radiologists iRefer guidelines
  • NICE Head Injury Guideline (assessment and early management)
  • Osborn AG. Osborn's Brain: Imaging, Pathology, and Anatomy, Elsevier
  • Grainger & Allison's Diagnostic Radiology, Elsevier

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.