Osteokinematics vs Arthrokinematics

Greetings fellow science enthusiasts!

This week's blog post is fairly short; I'm going to briefly explain the difference between Osteokinematics and Arthrokinematics. Let's start by breaking these words down into their roots and meanings. :)

Osteo = from the Greek osteon, meaning "bone"
Arthro = from the Greek word arthron, meaning "joint"
Kinematic/Kinetic = from the Greek word kenesis, meaning "motion or movement"

So Osteokinematics is simply bone movement and Arthrokinematics is joint movement. Another way to describe this would be that Osteokinematics is the movement that is happening around the joint and Arthrokinematics is the movement that is happening at the joint surface.

Osteokinematics is the gross movement that happens between two bones. This happens because our bone surfaces articulate at the joint. Osteokinematics typically consist of flexion/extension, abduction/adduction, and internal rotation/external rotation.

Arthrokinematics is the small movements happening at the joint surface. Arthrokinematic movements typically consist of rolls, glides/slides, and spins.

For example, when you raise your arm up, as if to ask a question, your humerus is moving upwards. The head of your humerus has to roll downward into the glenoid cavity to allow for this movement. So the Osteokinematic motion would be abduction of the humerus at the/of the glenohumeral joint while the Arthrokinematic movement is simultaneously occurring and moving the head of the humerus inferiorly via a glide/slide.

Neat stuff, eh? I'm sure I'll be revisiting this topic in the future in more depth, but in the mean time, consider this as a teaser to the complexity of movement in the human body. Thankfully it all works... Because Science!

Cheers!

Fliff

Here is an image I am shameless borrowing from my source for further reading: Clinical Gate. This kind of gives you an idea of what is happening in the shoulder movement I described above.

FURTHER READING:
Clinical Gate