Section 13-323. Medical board

a. (1) There shall be a medical board of three
  physicians.  One  of such physicians shall be appointed by the board and
  shall hold office at the pleasure of such board, one shall be  appointed
  by  the  commissioner of health and mental hygiene and shall hold office
  at the pleasure of such commissioner, and the third shall  be  appointed
  by  the  commissioner of citywide administrative services and shall hold
  office at the pleasure of such commissioner.
    (2) The board, the commissioner of health and mental hygiene  and  the
  commissioner  of  citywide administrative services shall each have power
  to appoint three alternate physicians, who  shall  hold  office  at  the
  pleasure  of  such  appointing  board or official. Whenever the board of
  trustees of the pension fund shall so direct, the functions, powers  and
  duties  of  the  medical  board,  in  addition  to  being  performed and
  exercised by the three physicians appointed pursuant to paragraph one of
  this subdivision, shall be performed and exercised by one or more groups
  of three physicians as hereinafter prescribed. Each such group of  three
  physicians  shall function separately as the medical board and each such
  group may consist partly of a physician or physicians appointed pursuant
  to such paragraph one and partly of one or more alternate physicians, or
  may consist entirely of alternate physicians;  provided,  however,  that
  one  of  the physicians or alternate physicians in each such group shall
  be appointed by the board, one by the commissioner of health and  mental
  hygiene and one by the commissioner of citywide administrative services.
    b. The medical board shall arrange for and shall pass upon all medical
  examinations  required  under  the  provisions of this subchapter, shall
  investigate all essential statements and certifications by or on  behalf
  of a member in connection with an application for disability retirement,
  and  shall  report  to  the  board  its  conclusions and recommendations
  thereon.