Mobile versions of the automedic technology installed in practically every starship and colony module in known space, medical droids are deployed in battlefield and expeditionary environments, where a static medical facility may not be feasible.
Medical droids have long been a staple of terran scifi, so it seemed natural that they should be instrumental in the development of the technology. The increasing weight of equipment and training required by medical corpsman in order to operate in hostile environments was creating a shortage of manpower to effectively cover deployments in non-colonized systems. By stripping a small starship automedic of most of its functions and optimizing for the most common battlefield trauma only, terran techs were able to house the unit in a mobile platform, and thus, the idea of the medical droid was born.
Although it is not necessary - and often impractical - for such droids to represent the physical stature of its patients, terran medical droids are frequently built to resemble a human form; research has shown that patients are more at ease with anthropomorphic models than with more practical designs.