According to the University of Washington School of Medicine, range of motion (ROM) is the amount of flexibility in your joints. ROM is usually measure in degrees from the starting position to the position at the end of its full range of movement. Some joints have the ability to move in more than one direction.
Extension/Hyperextension
Extension refers to the act of extending your body part, thus increasing the angle. For instance, a straight leg indicates your knee is fully extended. Some joints can move past full extension to hyperextension. According to the Merck Manuals, the normal extension of your knee is 120 degrees while your elbow can extend 145 degrees.
Flexion
Flexion occurs when you contract the muscle to decrease the angle between your bones. Drawing the heel up towards the buttocks or bending the elbow to draw the hand to the shoulder is an example of flexion. Your elbow can flex up to 160 degrees while your wrist can only flex up to 90 degrees.
Pronation/Supination
Pronation occurs when turning the palms of your hands to face downward. Supination occurs when your palms are rotated upwards. Your elbow and ankle joints can pronate and supinate. Turning your foot inward or outward is also called inversion or eversion. According to the Electronic Textbook of Hand Surgery, your forearm should pronate about 70 degrees and supinate about 85 degrees. Your foot should rotate about 35 degrees during inversion and about 25 degrees during eversion.
Abduction/Adduction
According to ExRx.net, your joint moves your body part away from your body in abduction. An example of abduction is when your arms are held at your sides then moved straight out away from your hips with your arms outstretched. Abduction occurs when moving your body part toward your body as when bringing your legs back together during a jumping jack. Normal ranges for hip abduction and adduction are about 45 degrees while the shoulders can move to about 90 degrees in both directions.
Medial/Lateral Rotation
Medial rotation occurs when bringing your forearm in towards the body as you do when you bring your hands together while clapping. Lateral rotation occurs when moving the forearm away from the body. Your hips can rotate about 45 degrees both laterally and medially while your shoulders can rotate to about 90 degrees.
Other ROM Examples
Other examples of ROM include transverse adduction, abduction, flexion and extension as well as retraction, protraction and circumduction.
References
- University of Washington School of Medicine: Range-of-Motion Exercises
- Merriam-Webster Online Dictionary: Extension
- Merriam-Webster Online Dictionary: Flexion
- The Merck Manuals: Physical Therapy
- Electronic Textbook of Hand Surgery: Normal Range of Motion Reference Values
- ExRx.net: Shoulder Articulations
