A passive holding arm for medical purposes, in particular for holding surgical mechatronic assistance systems and/or surgical instruments, comprising a proximal end for attaching the holding arm to a base and a distal end for receiving a surgical mechatronic assistance system and/or surgical instrument; at least one first and one second arm segment , wherein the first arm segment is connected to a first joint and the second arm segment is connected to a second joint , wherein each joint is actively braked but not driven and is releasable and lockable, wherein each of the first and second joints thereto comprises an electromagnetic brake having a permanent magnet, wherein the brakes are biased in an unpowered idle state in such a way that the joints are locked; and an operating unit for bringing the holding arm into a desired pose, wherein the operating unit is adapted to release the associated joint upon contact between an operator and one of the first and second arm segments , such that the first joint is released when a contact occurs between an operator and the first arm segment the second joint is released when contact occurs between the operator and the second arm segment ; a first interface at the proximal end for connecting the holding arm to an energy source and to an external control unit for transmitting signals to and from the holding arm ; wherein data can be provided about a pose of the holding arm at the first interface to transfer them at a surgical navigation system; a second mechatronic interface at the distal end for coupling the holding arm to the assistance system for controlling the assistance system ; and a transmission unit which is arranged inside the holding arm and which connects the first interface to the second interface in order to transmit energy and signals between the interfaces . at least one first and one second arm segment , wherein the first arm segment is connected to a first joint and the second arm segment is connected to a second joint , wherein each joint is actively braked but not driven and is releasable and lockable, wherein each of the first and second joints thereto comprises an electromagnetic brake having a permanent magnet, wherein the brakes are biased in an unpowered idle state in such a way that the joints are locked; and an operating unit for bringing the holding arm into a desired pose, wherein the operating unit is adapted to release the associated joint upon contact between an operator and one of the first and second arm segments , such that the first joint is released when a contact occurs between an operator and the first arm segment the second joint is released when contact occurs between the operator and the second arm segment ; a first interface at the proximal end for connecting the holding arm to an energy source and to an external control unit for transmitting signals to and from the holding arm ; wherein data can be provided about a pose of the holding arm at the first interface to transfer them at a surgical navigation system; a second mechatronic interface at the distal end for coupling the holding arm to the assistance system for controlling the assistance system ; and a transmission unit which is arranged inside the holding arm and which connects the first interface to the second interface in order to transmit energy and signals between the interfaces . <EOS>