A robotic arm control system comprising: a medical instrument configured to be reversibly inserted into a body-part of a living subject; a force sensor configured to detect a force applied by the medical instrument to the body-part; a robotic arm attached to the medical instrument, the robotic arm including a plurality of robotic joints configured to control movement of the robotic arm and manipulate the medical instrument; a first position sensor configured to track an instrument position of the medical instrument in the body-part; a second position sensor disposed on the living subject and configured to track a body position of the body-part during the insertion of the medical instrument in the body-part; and a controller configured to: compute, responsively to the instrument position and the body position, a location of the medical instrument relative to the body-part; register a medical scan with respect to at least one given location of the body-part, the medical scan including an image of an anatomical feature at the computed location, wherein the image of the anatomical feature has a radiodensity; identify that the anatomical feature is at the computed location of the medical instrument based on the registration of the medical scan and the instrument position; set a permitted force level for application to the anatomical feature based on the radiodensity of the image of the anatomical feature; compare the detected force applied by the medical instrument to the permitted force level for application to the anatomical feature at the computed location; and send a control command to, or cut power of, the robotic arm to loosen a rigidity of at least one robotic joint of the plurality of robotic joints in response to the detected force applied by the medical instrument at the computed location being greater than the permitted force level. a medical instrument configured to be reversibly inserted into a body-part of a living subject; a force sensor configured to detect a force applied by the medical instrument to the body-part; a robotic arm attached to the medical instrument, the robotic arm including a plurality of robotic joints configured to control movement of the robotic arm and manipulate the medical instrument; a first position sensor configured to track an instrument position of the medical instrument in the body-part; a second position sensor disposed on the living subject and configured to track a body position of the body-part during the insertion of the medical instrument in the body-part; and a controller configured to: compute, responsively to the instrument position and the body position, a location of the medical instrument relative to the body-part; register a medical scan with respect to at least one given location of the body-part, the medical scan including an image of an anatomical feature at the computed location, wherein the image of the anatomical feature has a radiodensity; identify that the anatomical feature is at the computed location of the medical instrument based on the registration of the medical scan and the instrument position; set a permitted force level for application to the anatomical feature based on the radiodensity of the image of the anatomical feature; compare the detected force applied by the medical instrument to the permitted force level for application to the anatomical feature at the computed location; and send a control command to, or cut power of, the robotic arm to loosen a rigidity of at least one robotic joint of the plurality of robotic joints in response to the detected force applied by the medical instrument at the computed location being greater than the permitted force level. compute, responsively to the instrument position and the body position, a location of the medical instrument relative to the body-part; register a medical scan with respect to at least one given location of the body-part, the medical scan including an image of an anatomical feature at the computed location, wherein the image of the anatomical feature has a radiodensity; identify that the anatomical feature is at the computed location of the medical instrument based on the registration of the medical scan and the instrument position; set a permitted force level for application to the anatomical feature based on the radiodensity of the image of the anatomical feature; compare the detected force applied by the medical instrument to the permitted force level for application to the anatomical feature at the computed location; and send a control command to, or cut power of, the robotic arm to loosen a rigidity of at least one robotic joint of the plurality of robotic joints in response to the detected force applied by the medical instrument at the computed location being greater than the permitted force level.