The architectural structure has a strongly longitudinal layout, with the church at its center, which is the fulcrum of two long corridors, approximately nine meters high, at the ends of which are the protruding volumes of the service areas and servants' quarters. The function of the church, located at the center of the corridors, was to divide the long infirmary into two sub-corridors, one for men and one for women.
The typological scheme fits, albeit with particularly large dimensions, into the more general Roman hospital tradition of longitudinal aisles and an adjoining church. The real typological innovation is precisely the large longitudinal development, which implies the need to articulate and characterize the external façades, and in particular the façade on Vicolo delle Fratte, where all the decorative elements are concentrated, starting from the convex façade of the church, compared to the side façades.[2]
The hospital facilities also included an apothecary and an anatomical theater built in 1826 by Leo XII.
Authoritative sources (Argan) indicate San Gallicano as an exemplary case in the field of sanitary engineering evolution, so much so that it was considered the best of its kind in Europe at that time. In 1932, the ISG and the Regina Elena Institute (IRE) were merged under a single administrative body, the “Istituti Fisioterapici Ospitalieri” (IFO). Over the years, the historic building in Trastevere was abandoned by the traditional public institute.
It is currently the headquarters of the Community of Sant'Egidio and the INMP, a public body of the national health service, established in 2007 to address the social and health challenges faced by the most vulnerable populations and supervised by the Ministry of Health.[3]