An instrument holder (50) is described for mounting a medical instrument (102) on a joint arm (10), said instrument holder comprising a housing (56), a holder formed on the housing (56) in order to hold the medical instrument (102), and a coupling device (52) formed on the housing (56) in order to attach the housing (56) to the joint arm (10). The holder has a receiving groove (80) adapted to a part (104) of the medical instrument (102), in which receiving groove (80) this instrument part (104) is receivable, and an elastic pull strap (82) that is attachable to the housing (56) in such a manner that it surrounds the receiving groove (80) together with the instrument part (104) arranged in the receiving groove (80) in order to hold the instrument (102).
