Definition:

An Aid Station is an installation for the first aid care and treatment of the sick and wounded, established under combat conditions by a Section of the unit’s Medical Detachment. The Regimental Section and each of the (three) Battalion Sections are equipped to establish and operate an Aid Station.
TM 20-205 “Dictionary of United States Army Terms” defines an Aid Station as follows: a First-Aid Post or Center established by the Medical Department on the route of evacuation from a combat area to which the wounded are brought, also called Dressing Station or First-Aid Station. The wounded are given first aid and separated into groups according to their injuries; those needing further care are prepared for transportation to the rear.
An Aid Station is arranged so as to provide a place where casualties can be received and await medical treatment, a place for treatment of seriously wounded and another for slightly wounded, and a place where casualties can await further evacuation.

The Regimental Aid Station was established by the Headquarters Section (Medical Detachment) and ordinarily served the Regimental Headquarters and Companies that were not parts of Battalions. It was in the same echelon of evacuation as were Battalion Aid Stations. This means that casualties were rarely evacuated from a Battalion Aid Station to the Regimental Aid Station.  However, it could take over casualties of a Battalion Aid Station that was forced to move before it could be evacuated. It was set up in the area of the regimental reserve so that its Section with the reserve could remain in readiness for movement. In some situations, the Regimental Aid Station was not established and Headquarters Section personnel could be assigned and used elsewhere!

A Battalion Aid Station was established by a Battalion Section (one per each Battalion) to serve a Battalion, including any supporting elements in the Battalion area and any Detachments from the Battalion. Its purpose was to treat and care for casualties while awaiting their further evacuation. Battalion Aid Stations were not established during a rapid advance, only that part was established as immediate circumstances required. During an attack, the Battalion Aid Station would be located as far forward as protection permitted, and the Litter carry was to be kept as short as possible to allow for prompt evacuation and basic treatment, and to ease the task of the Litter Bearers. This type of Aid Station was often moved by leapfrogging part of its personnel and equipment to another site, while the remaining group continued to function until such time as the part which had moved was ready to receive casualties again – it would only then move to its new location, leaving medical attendants to care for any remaining casualties.

Since there was only one Veterinary Aid Station in a Regimental Medical Detachment, it was set up by the Veterinary Section to serve all animals in the Regiment (in case animals were still in use).

Desirable Features for Selecting an Aid Station Site:

The physical features of the site of an Aid Station could vary from a comfortable building to a few square yards of ground without shelter from the elements, usually under tentage. It must be noted that it was difficult to find a site that satisfied all requirements, but following features were highly desirable:

• Protection from direct enemy fire
• Convenience to troops served
• Economy in litter carry
• Accessibility to supporting medical troops
• Proximity to natural lines of drift of wounded
• Facility of future movement of the Aid Station to the front or rear
• Proximity to water
• Protection from the elements

Remark:
Terrain features or military establishments that invited enemy fire or air action were to be avoided as sites for Aid Stations. Especially to be kept away from were prominent landmarks, bridges, fords, important road intersections, artillery and heavy weapons positions, ammunition depots, and other distributing points. Another undesirable feature was proximity to an exposed flank.
The location of an Aid Station would vary within wide limits, depending upon the military situation. No definite rules can, or should be laid down, but the following may be offered as a general statement of the type of an Aid Station of an Infantry Battalion in the frontline: a centrally-located site, from 300 to 800 yards to the rear of the frontline, combining as few undesirable features with as many desirable ones, as can be had in the terrain available.

Functions of an Aid Station:

• Reception and recording of casualties
• Examination and sorting of casualties; returning the fit to duty
• Dressing or re-dressing of wounded; treatment limited to that necessary to save life or limb and to prepare patients for evacuation for short distances; administration of narcotics and prophylactic sera
• Prophylaxis and treatment of shock and exhaustion with hot food and drinks
• Temporary shelter of casualties, when practicable
• Transfer at the Aid Station of evacuees to the supporting medical echelon, usually to Ambulances or Litter Bearers of a Collecting Company

General Operating Procedures:

The Aid Station of a unit was established only when movement of this unit was unsteady, very low, or halted altogether. Usually only such part was set up as immediate circumstances required, or for which need could be foreseen.
During attack, rapid forward movement of combat elements is usually associated with small losses, and casualties could then be collected by Litter Squads into small groups of advance and given first aid. Such casualties could thus be evacuated promptly by the medical unit in close support, thus relieving the need for a truly established Aid Station and permitting the Medical Section to keep up with the combat troops.
In defense, a Battalion Aid Station was usually located somewhat farther to the rear, its exact site was determined by the individual characteristics of each center of resistance and the specific tactical situation. The Aid Station was completely established, but it was kept mobile with those units held in mobile reserve.
During withdrawal, delaying action, or retreat, Aid Stations would displace rearwards by bounds, and occupy installations successively echeloned to the rear. Temporary Aid Stations were to be set up near the avenues of rearward movement. If necessary, additional Ambulances and Litter Bearers from the Division medical service were called upon to reinforce the unit’s Medical Detachments. All available transportation is utilized for evacuation of wounded in order to prevent their capture; but casualties that cannot be evacuated must be abandoned (command decision). Whenever it became necessary to abandon sick and wounded to the enemy, medical personnel with essential equipment and supplies were to be left with the casualties at the medical installation under the protection of the Geneva Convention flag, until the enemy had taken them over.
An Aid Station must keep at all times in contact with the unit it serves and supports. It must be moved, by echelon if necessary, as soon as movement of the combat elements makes its location unsuitable!
It should be noted that an Aid Station was not the proper place for the initiation of elaborate medical treatment. Such measures would only retard the flow of casualties to the rear and immobilize the Station and its personnel.

Organization of an Aid Station:

The organization of an Aid Station depended upon the unit and the situation. In general, the functions of recording, examination, sorting, treatment, and disposition must be provided for in every situation. These will require one or more Medical Officers, assisted by Noncommissioned Officers and Enlisted Medical and Surgical Technicians. The allocation of personnel to these functions was the responsibility of the Regimental Surgeon, also Headquarters Detachment Commander.

According to T/O 7-11 dated February 1944, the Medical Detachment (Infantry Regiment) consisted of 9 Officers and 126 Enlisted Men (T/O 7-11 of March 1943, indicates 9 Off & 103 EM).
Regimental Aid Station personnel consisted of 2 Dental Officers (CO + Asst), an NCO (1 Sgt) and Enlisted Technicians (19). Field support was provided by the Company Aid Squad, consisting of 8  Aidmen, detached to the different Companies.
Each Battalion Aid Station usually consisted of 2 Officers, the Battalion Surgeon, his assistant (MAC Officer), a number of NCOs (2) and Medical or Surgical Technicians (6) . A Staff Sergeant further assisted and handled adequate emergency treatment when both Officers were absent; in addition, he was responsible for general supervision of EM and of supplies. The medical assistant (MAC Officer) routinely gave emergency treatment to the slightly wounded and prepared casualties for evacuation. He was assisted by a Corporal. The other Enlisted Medical and Surgical Technicians received casualties, sterilized instruments, administered hypodermic medication, performed shock nursing, and set up and moved the Station equipment. Additional support was provided by the Company Aid Squad (12 aidmen) and Litter Bearer Squad (12 men). Some Privates combined administrative jobs and drove the available vehicles.

Equipment of an Aid Station:

The equipment of an Aid station was limited to the instruments, medicines, foods, blankets, and litters necessary for the emergency care and treatment of casualties, and especially battle injuries. Organizational equipment largely consisted of Medical Chests, such as MD # 1 with surgical dressings; MD # 2 with drugs, instruments, and sterilizer; MD # 4 with table, desk, stools, and typewriter; two MD # 60 with dental chair, foot drill, medicine cabinet, instruments and drugs; as well as gas casualty chest, litters, imprinting machines, blanket sets, and splints – and additional items, such as cocoa units, Lyster bag, buckets, dressing table, lantern units, axes, shovels, picks, rope, and surplus supplies. Moreover, each Battalion Section had two identical sets of 5 Medical Packs with dressings, drugs, instruments, sterilizers, blankets, and 5-gallon water cans. There were 4 CP tents, i.e. 1 for the Headquarters Section, and 1 for each Battalion Section, in order to provide the necessary shelter for the Aid Stations. All the equipment was divided into basic loads, that, when necessary, could be transported by hand. It usually was sufficiently compact to be transported in one vehicle (cargo type) used in the unit, or on pack animals. If necessary, vehicles, such as light trucks including trailers, could easily be converted into patient carriers. At the same time, it was ample enough to initiate and sustain combat until replenishment could be made by the Division medical service. It was all combat equipment, and the transport carrying it travelled with that part of the unit train which carried spare ammunition and other materiel essential in combat. Each Aid Station was to be clearly identified by Red Cross Markers (unless the complete installation was to be concealed for tactical or camouflage reasons). Needless to add that medical personnel, such as Officers and Enlisted Men, each carried the necessary individual First-Aid Kits and the appropriate Geneva Convention Brassards and ID documents.

Remark:
When dealing with Aid Stations (set up by personnel belonging to the Medical Detachment, Infantry Regiment),  it must be noted that, all together, the 4 Medical Detachment Sections (i.e. 1 x Headquarters Section + 3 x separate Battalion Sections) numbering 9 Commissioned Officers and 126 EM, only disposed of following Vehicles: 1 Truck, 2 ½-Ton, Cargo, 7 Truck, ¼-Ton, and 7 Trailer, ¼-Ton.

Camouflage of Medical Installation:

In a Theater of Operations, the camouflage of Medical installations was a command decision. However, the tactical disposition of friendly troops could be disclosed by conspicuous medical installations, so it was usually advisable to camouflage them. Since advanced medical installations were usually only temporary in character and location, the problem of camouflage was greatly simplified through employment of the following means:

• Careful choice of position under natural cover or in buildings
• Hasty camouflage measures to supplement inadequate natural concealment
• Selection of inconspicuous or concealed access routes before occupying a position
• Camouflage discipline to avoid making careless tracks and to prevent unnecessary exposure of vehicles, equipment, or personnel to enemy observation in daytime
• Complete blackout at night

Further instructions, part of the check list for bivouacs, also applied to medical installations:

• Avoid sites near landmarks
• Construct any required camouflage quickly to avoid delay in use of the installation
• Litter Bearers must use concealed routes whenever possible
• Preliminary examination rooms should be light-tight
• Tone down metal chests, pails, and shiny objects with dull paint
• Ambulances must stop under cover
• Park vehicles in concealed areas to rear of installation
• Bury empty bottles and other empty and shiny containers

Instructions applying to Collecting Stations:

• Must have a sheltered place for vehicles to load, unload, and turn
• Turn-off roads from main roads to Stations must be concealed or carried past the Station

Instructions applying to Clearing Stations:

• Locate in large civilian buildings when possible. Permanent cover is always preferable to tents
• When tentage is required, erect the minimum number needed, and only under overhead concealment
• Color tents to match surroundings

Instructions applying to Medical Vehicles:

• Keep vehicles always dispersed
• Cover vehicles with drapes when parked
• When Red Cross (Geneva Convention) insignia are ordered covered, do not paint them out, cover them with tarpaulin or other olive drab-colored materiel

Remark:
The Medical Detachment was usually equipped with the necessary camouflage nets, issued as authorized by the Theater of Operations Commander. Their official designation was Net, Camouflage, Cotton, Shrimp, 22 feet x 22 feet (1/4-Ton Truck), and 36 feet by 44 feet (1 ½-Ton and 2 ½-Ton). These Nets could then be garnished with burlap, osnaburg, salvaged fabrics, captured fabrics, locally manufactured fabrics, or natural materials depending of their availability, adaptability, and camouflage properties.