Field hospital

A field hospital is a temporary medical facility set up close to military operations to treat the wounded and sick before they can travel to permanent hospitals. The term is used loosely for any improvised hospital near a battle, and precisely, in some armies, for a specific unit with its own staff, equipment and size.

The Roman army had medical staff, and its stone fortresses include buildings long interpreted as hospitals (valetudinaria), though scholars debate how confidently they can be identified. Temporary infirmaries on campaign are much harder to trace.

In the American Civil War, under Jonathan Letterman's system, Union divisions set up field hospitals behind the lines, often in barns, churches and houses. In the First World War the British chain ran through dressing stations and casualty clearing stations. In the Korean War, the US Army's Mobile Army Surgical Hospitals put surgeons close to the front, and helicopters brought patients to them.

1. Siting. Close enough to receive casualties quickly, far enough to be out of direct fire, near water and a road.
2. Shelter. Tents where they could be carried; existing buildings where they stood.
3. Work. Surgery for wounds that could not wait, dressings, splints and sorting.
4. Moving on. Patients went to larger hospitals as soon as they could travel, so the field hospital could take the next arrivals, or the hospital itself moved with the army.

• Vindonissa, about AD 35. Museum Aargau identifies a large hospital at Vindonissa, built first in wood and later in stone. Whether a permanent hospital stood there in AD 35, or only a timber predecessor or field infirmary, is an open question in The Hands That Survived Rome.