Final answer:
A bone that gets separated from a joint, causing loss of joint function, is known as a dislocation.
Step-by-step explanation:
A bone that is normally in contact with a joint but becomes separated from that joint, causing loss of joint function, is termed a dislocation. This injury disrupts the normal relationships and alignment between bones at a joint, which can be quite painful and immobilizing. Options like fracture, separation, and dorsiflexion are different terms describing other conditions or movements. A fracture is when the bone itself is broken, a separation might refer to a more general parting of tissues, and dorsiflexion is a specific type of movement at a joint.