What does "extension" mean in the context of body movement?

In the context of body movement, "extension" specifically refers to the action of straightening a limb or body part, effectively increasing the angle between two body segments. For instance, extending the arm involves moving it away from the body, straightening the elbow joint, and increasing the angle formed at that joint. This action contrasts with flexion, which involves bending that decreases the angle between body parts.

Understanding this term is essential for accurately documenting movements in clinical settings, as it helps define the nature of patient mobility and rehabilitation needs. The correct identification of "extension" as a straightening motion is foundational in various medical fields, including physical therapy, anatomy, and kinesiology.