In this article we give an overview of biaxial joints, examples of biaxial joints and explain their function. We also give some sporting and exercise examples of how this contribute to movement.
What is a biaxial joint?
A biaxial joint is a type of joint that allows movement around two axis, allowing movement through two planes of motion. In the human body these ranges of movement are usually flexion/extension, along with abduction/adduction. Biaxial joints differ from other joint types in that provide two ranges of motion.
What are examples of biaxial joints?
Examples of biaxial joints include the knuckles (metacarpophalangeal) and the joint at the base of the thumb (carpometacarpal joint). The knuckle (metacarpophalangeal) is an example of a biaxial, condyloid joint, allowing our fingers to flex/extend and spread apart and back together again (abduction/adduction).
What types of joints are biaxial joints?
The most common types of joints found in the human body are synovial joints. These are made up of six joint shapes: hinge, pivot, ball & socket, ellipsoid, saddle and plane joints. The following are classified as biaxial joints:
- Condyloid joints
- Saddle joints
If you find a joint classified as one of the above, it will always have two ranges of motion and therefore be a biaxial joint.
Sporting actions using biaxial joints
Sporting actions that use biaxial joints are those that require actions from the joints described above – think about actions that require gripping or holding with our hands and feet. Examples include gripping your opponent during a grapple in wrestling and flexing your toes into a hold during rock climbing to maximise your grip.
Related terms to biaxial joints
In more medical texts you may also come across biaxial joints referred to as biaxial articulations. Articulations are points where two or more bones meet, not all articulations provide movement, such as the various bones that make up the skull.
Joints that provide only one axis of movement are known as uniaxial joints, whereas joints that offer three axis of movement are known as triaxial / multiaxial joints. Click the links below to read related articles on each topic:
Summary
You should now know that biaxial joints allow movement around two axis, you should also know where they can be found in the human body and be able to give sporting examples of their use.
As a sport scientist or coach learning about basic anatomy can feel distant from what you wish to do in practice. However, having a detailed understanding of joints, how they work and the actions they allow for allows for a far greater analysis of sporting actions, allow you to better detect where errant technique may come from and what coaching command may help an athlete improve their movement.
Will is a sport scientist and golf professional who specialises in motor control and motor learning. Will lecturers part-time in motor control and biomechanics, runs Golf Insider UK and consults elite athletes who are interested in optimising their training and performance.