The synovial joints of the human body allow for large ranges of movement. These movements are the result of muscles relaxing and contracting. When naming these movements, anatomists generally pair together one motion with its direct opposite. References to anatomical motions assume the body is in an upright stance with arms to the side and palms facing forward, like Da Vinci's Vitruvian Man. Two such paired movements are flexion and extension.


1. Anatomical Planes

Three principal planes allow for accurate descriptions of motion. The sagittal plane bisects the body, separating it into left and right sides. The coronal plane also divides the body down the middle, but in the other direction, designating the dorsal and ventral or back and front portions. The transverse plane is the only horizontal plane, and it divides the body into cranial or upper body and caudal or lower body.

what is flexion and extension PALMIHELP / Getty Images

More on Facty Health


This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.