Jackson Posture Center & Massage Therapy Clinic

06/25/2025

05/03/2025

04/19/2025

Yep

04/14/2025

04/14/2025

We are empowered to be able to figure out any and all joint actions of a muscle by looking at one simple thing… 😊

the line of pull of the muscle relative to the joint it crosses.
Or put in a bit more detail…
the line of pull of the muscle relative to the axis of motion at that joint.

How can we understand this?

Well. We need to understand planes and axes.

Movement of the body through space is divided into three dimensions (3D), each dimension represented by a plane.

There are three (cardinal/major) planes:
sagittal
frontal (aka coronal)
transverse (aka horizontal)

We need need to see that all axial movements that occur within a plane (and most movements are axial) occur around an axis.

An axis is an imaginary line that runs through the center of the joint (and is always perpendicular to the plane).

It is not my goal here to teach planes and axes, all therapists out there should have already studied them. My goal here is to refresh these ideas and point out that by knowing them, we are tremendously empowered!

Look at where the hamstrings cross the hip joint. Yes, they cross posteriorly, so the do extension of the thigh at the hip joint.

But look at how they cross medial to the center of the hip joint (where the axis would be)… 👀 👀😊

What does this tell us? 🤔

In the frontal plane, the hamstrings ADDUCT the hip joint.
And all three hamstrings (medial and lateral) do this because they all cross medially!! 👏🏽👏🏽👏🏽

It really is sooooooo simple.

I hope this helps you understand how utterly simple muscle function is.

Feel free to leave a comment or reply 😊

04/08/2025

Slow Down Y’all Breathe in this Awesome Day

04/08/2025

04/07/2025