When missiles and drones strike populated areas, the images that follow tend to show destroyed buildings and burning streets. What they rarely capture is what happens inside the bodies of those nearby, including people who walk away apparently unharmed.
The injuries caused by modern explosive munitions are wide-ranging, often hidden, and can develop hours or days after the initial blast. Understanding them matters, not least because many of those affected in conflict zones are civilians, without the protective equipment that gives soldiers some defence against the worst effects.
The blast wave
The first thing to hit the body is invisible. Every explosion sends out a pressure wave travelling at enormous speed - up to 9,000 metres per second - that passes through tissue, organs and bone in an instant.
The body's air-filled structures are most vulnerable. In the lungs, the wave compresses and then rapidly decompresses delicate tissue, causing bruising , tearing and internal bleeding. This "blast lung" can fatally disrupt the lungs' ability to exchange oxygen and may kill within minutes.
The ears are similarly exposed. Even relatively small explosions - involving less than 80kg of explosive material - can damage the eardrum and the sensory nerves responsible for hearing. One study found that being within ten metres of a detonation makes hearing loss eight times more likely. In around one in three blast-related ear injuries in military personnel, the nerve damage is permanent.
The brain is particularly susceptible. Consisting of around 80% water , it is highly sensitive to pressure changes, and in built environments the blast wave bounces off walls and surfaces, converging from multiple directions at once. Evidence from Iraq and Afghanistan suggests that almost half of military personnel exposed to blasts suffered some form of brain injury - the leading cause of disability and death in those conflicts. Civilians face even greater risk, lacking helmets and body armour.
Symptoms range from concussion and disorientation - the "shell shock" of earlier wars - through to diffuse axonal injury , where the brain's internal wiring is stretched and torn, and bleeding or swelling within the skull. Some effects are immediate; others emerge over hours or days as blood vessels in the brain narrow in response to the pressure , restricting blood flow to critical areas.
The eyes - fluid-filled and exposed - are also at risk. Blast injuries to the eye frequently have poor outcomes and can include ruptured globes, traumatic cataracts and a range of other serious damage . The heart and aorta can also be affected, in some cases causing a fatal cardiac event , while changes in heart rate, breathing and blood pressure may follow even in those not directly struck.
Abdominal organs are not spared. The small intestine, spleen and liver are the most commonly injured , though symptoms may not appear until well after the explosion.
Flying debris and the blast wind
Those who survive the initial pressure wave face further hazards almost immediately. Fragments of building materials, glass and metal become high-velocity projectiles, causing lacerations and penetrating injuries. This is followed by the blast wind - a powerful rush of air that can exceed hurricane force and hurl people against walls, vehicles and rubble.
The resulting injuries are similar to those seen in high-speed road traffic collisions: fractures, bruising , traumatic brain injury and, in severe cases, traumatic amputation .
Those who are then buried under collapsed structures face crush injuries, asphyxiation, and the risk that muscle breakdown from sustained compression will damage the kidneys or trigger cardiac complications .
The hidden toll
What makes explosive injuries particularly difficult to assess, and to treat, is that their full extent is often not immediately apparent. A person who appears to have escaped serious harm may be carrying internal injuries that only become life-threatening hours later.
In conflict zones, where hospitals are frequently overwhelmed and access to care is limited, this delay can be fatal. The visible destruction captured in satellite images and news footage represents only part of the picture. For many survivors, the damage is invisible, and the consequences can last a lifetime.
Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
