In blast injuries from high-order explosives, primary blast injury characteristically affects which organ systems first?

• A Solid organs (spleen, liver) — rupture from shockwave compression
• B Skeletal muscle — myonecrosis and rhabdomyolysis
• C Gas-containing organs (lungs, gut, middle ear) — blast lung, intestinal perforation, tympanic rupture ✓
• D Central nervous system — direct pressure wave concussion

Explanation

Primary blast injury results from the direct effect of the overpressure (shock) wave. Air-tissue interfaces in gas-containing organs are maximally susceptible to pressure wave damage due to impedance mismatch between air and tissue. Blast lung (pulmonary barotrauma with haemorrhagic alveolar contusions), intestinal perforation and haemorrhage, and tympanic membrane rupture (a sensitive indicator of exposure) are the hallmarks. Solid organs sustain secondary injury from ground shockwave transmission or tertiary/quaternary injuries. The tympanic membrane rupture threshold is approximately 35 kPa overpressure.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

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Written and medically reviewed by the StethoPrep medical team.