Why does haematogenous osteomyelitis in adults most frequently affect the vertebral bodies rather than the long bone metaphyses that are typical sites in children?

• A Adult vertebrae have a richer nerve supply than long bones
• B Adults have weaker immunity in the axial skeleton
• C After physeal closure, metaphyseal vessels anastomose freely, while vertebral bodies retain end arteries with slow sinusoidal flow ✓
• D Long bone marrow becomes fatty and therefore more susceptible

Explanation

Once the physis closes, its vascular barrier disappears and metaphyseal and epiphyseal circulations anastomose, removing the sluggish non-anastomosing loops where bacteria lodge in childhood. In contrast, vertebral bodies are supplied by segmental arteries ending in dense sinusoidal networks with slow flow, favouring bacterial seeding, which is why vertebral osteomyelitis predominates in adults over 50.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.