Joy boomed from the speaker on the reception desk, the irrepressible rhythm of reggaeton transforming the waiting room of a South Bronx medical clinic into a late-afternoon Zumba class.

Teenagers from Honduras and Guatemala were shimmying to the beat, their workout part of an unusual form of therapy for many who had endured unimaginable trauma not so long ago. About the same time, in the quiet of Exam Room 10, a lawyer was preparing immigration documents for his client to sign.

Here, at this outpost of Montefiore Medical Center, exists what is believed to be the only legal-medical partnership in the country designed specifically for children who crossed the Mexican border illegally and are trying to settle into their new communities. Known as Terra Firma, the program began in October 2013, months before the surge of unaccompanied minors entering the United States.

While immigrants’ advocates have consistently deplored the dearth of lawyers to meet the needs of the new arrivals, their focus is now shifting: It has become clear to lawyers and advocates alike that mental health services with Spanish-speaking therapists are also desperately lacking.