In adults and IV drug users, which bone is most commonly affected by acute osteomyelitis?

Acute osteomyelitis in adults, particularly in intravenous drug users, is most commonly associated with the vertebral spine. This can be attributed to several factors. The vertebrae have a rich vascular supply and can be easily infected through hematogenous spread, especially when the skin's integrity is compromised. IV drug users often introduce bacteria directly into the bloodstream through contaminated needles, leading to a higher likelihood of seeding infections to the vertebral bodies.

Moreover, osteomyelitis in the vertebrae may present with back pain, fever, and neurological deficits if there is involvement of adjacent structures, making early recognition crucial for treatment. The condition may also arise in those with chronic conditions that compromise immune function, increasing the risk for this specific location of infection. The combination of these factors makes the lumbar and thoracic spine critical sites for osteomyelitis in this population.

While the other bones listed can certainly be affected by osteomyelitis, particularly the tibia in cases related to open fractures or other types of trauma, they are not as commonly involved in this specific context as the vertebral column.