Flexion vs. Extension

Yesterday, I spoke briefly about the three major planes of movement. Today, I will talk about segmental movements, as well as the axis around where the movements take place.

I like to simplify things in order for it to make sense in my head. Most people won’t walk around calling everything an axis. Think of an axis as the point of movement. The center. Where it’s taking place. Here are some examples of segmental movements at the focal point of where it’s occurring.

FLEXION
EXTENSION

The mediolateral axis (the center of rotation running towards the midline (medial) and away from the midline (lateral) ) for these images would be the shoulder joint. In the first photo, the arm is flexing upwards towards the body. This is known as “flexion”. I’ve come to notice that anything flexed TOWARDS the body, or moved towards the body is flexion. Any time the movement is AWAY from the body, it’s extension, like in the second photo. Another example:

Here, the mediolateral axis is the elbow joint, and from there, moving the arm up towards the body is flexion. Extending outwards would be extension.

An example during a work out routine: if you are doing leg extensions, the mediolateral axis would be the knee joint. When moving the leg(s) back towards the body, this would be FLEXION. As you push out, it’s an EXTENSION.

Now, here’s where it’s a little different. When it comes to the feet, it’s the same idea but called something different, due to it being the feet.

The mediolateral axis is the ankle joint. Now, when you flex the foot up towards the body, it’s still a flexion, but called DORSIFLEXION. And when you move the foot down away from the body, it’s called PLANTARFLEXION instead of anything related to extension.

The anteroposterior axis ( extending along a direction or axis from front to back) for this image is the vertebral column. If this image moved it’s body from the waist up to the left, it would be called LATERAL FLEXION (left). And if it moved to the right, LATERAL FLEXION (right).

Another example of the anteroposterior axis for the hip joint:

If you move your leg out, it’s called ABDUCTION, and inwards would be ADDUCTION. Think of those machines at the gym, where you sit down and press your legs outwards, or back in. Those machines are called either an ABDUCTOR or ADDUCTOR. Now you know why. When you move your body parts away from the midline of your body, it’s abduction. Moving it towards the midline is adduction.

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