🦴 Section 721.3 · Cervical Anomalies & Instabilities

Nelson Textbook of Pediatrics 22nd Edition | Cervical spine anomalies include os odontoideum, occipitalization of atlas, basilar invagination, and ligamentous laxity syndromes. Atlantoaxial instability (AAI) most common in Down syndrome (4-30%) — atlanto-dens interval (ADI) >4.5mm on flexion radiograph. Os odontoideum: separated ossicle of dens, C1-C2 instability, risk of myelopathy. 22q11.2 deletion syndrome: universal cervical anomalies (platysia, C2-C3 fusion, dysplastic dens). Evaluation: flexion/extension radiographs, MRI for neurologic symptoms. Treatment: activity restriction for asymptomatic instability; C1-C2 fusion for symptomatic instability or myelopathy.

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📋 30 Clinical Scenarios — Cervical Anomalies & Instabilities

📇 High‑Yield Review Cards

🩺 Clinical Recognition: Cervical Anomalies & Instabilities

Select a presentation to review diagnostic clues and management per Nelson 721.3.

📋 Stepwise Management of Cervical Anomalies & Instabilities

🔑 Key Principles — Nelson Section 721.3
• Atlanto-dens interval (ADI): Normal <3mm; Down syndrome <4.5mm. ADI >10mm = frank instability.
• Down syndrome AAI: 4-30%. Screening radiographs (neutral, flexion, extension) at age 3-5 years if symptomatic or for Special Olympics. Asymptomatic with ADI >4.5mm → avoid contact sports.
• Os odontoideum: Congenital anomaly of dens → C1-C2 instability. MRI for cord compression. C1-C2 fusion if symptomatic or instability.
• 22q11.2 deletion syndrome: Universal cervical anomalies. Advanced imaging recommended.
• Myelopathy symptoms: Gait disturbance, hyperreflexia, clonus, Babinski, clumsiness, bowel/bladder changes.

    ⚡ Reflex Prompts — Clinical Decisions

    📖 Summary: Cervical Anomalies & Instabilities (Nelson 721.3)