An instrument support apparatus is disclosed. In some embodiments, the instrument support apparatus may be for supporting an instrument having a shaft extending along a shaft axis relative to a patient positioned adjacent to an external frame. In some embodiments, the instrument support apparatus may include a base fixedly mountable onto the external frame, a pivot assembly mounted for pivoting relative to the base, an arm assembly extending along a longitudinal axis, and a support assembly configured to support the instrument on the arm assembly.