Extending a joint beyond its normal anatomical position is called what?

Extending a joint beyond its normal anatomical position is called hyperextension.

The term describes movement past a joint’s usual extension limit. Extension generally straightens a joint or increases the angle between bones; hyperextension carries that motion beyond the neutral or customary range. The amount considered excessive varies by joint and by individual anatomy.

Some people naturally have mild hyperextension, especially at the elbows, knees, fingers, or spine, without pain or injury. In other cases, a sudden force can push a joint too far and strain ligaments, tendons, muscles, or the joint capsule. A hyperextended knee, for example, may damage supporting structures even when no bone is broken.

Hyperextension is often confused with hypermobility. Hyperextension describes a particular movement, while hypermobility refers more broadly to unusually loose or flexible joints. Controlled flexibility is not automatically harmful, but painful or traumatic hyperextension may require medical evaluation.