Joint Movement: Osteokinematic and Arthrokinematic Types, Importance, and Applications

What are the two major types of joint movement?

The two major types of joint movement are osteokinematic movements, which are the gross, visible motions of bones, and arthrokinematic movements, which are the small, involuntary motions occurring between joint surfaces.

Understanding Joint Movement: A Foundational Concept

The human body is a marvel of engineering, and its ability to move is largely thanks to the intricate design of its joints. From a simple finger tap to a complex Olympic lift, every action involves movement at one or more articulations. To truly understand exercise, rehabilitation, and injury prevention, it's crucial to differentiate between the two fundamental categories of joint motion: osteokinematic and arthrokinematic movements. While distinct, these two types of movement are inextricably linked and function synergistically to allow for efficient and pain-free motion.

Type 1: Osteokinematic Movements

Osteokinematic movements refer to the gross, observable movements of bones relative to one another at a joint. These are the motions we typically describe and measure when discussing range of motion (ROM) in anatomy and exercise. They occur in the cardinal planes of motion (sagittal, frontal, transverse) and are usually voluntary and controlled by muscle contractions.

Key Characteristics of Osteokinematic Movements:

• Visible and Measurable: These are the movements you can see and quantify using tools like goniometers.
• Voluntary: They are consciously initiated and controlled by the central nervous system.
• Occur in Planes: Movements happen around axes of rotation within the anatomical planes.

Common Examples of Osteokinematic Movements:

• Flexion: Decreasing the angle between two bones (e.g., bending the elbow).
• Extension: Increasing the angle between two bones (e.g., straightening the knee).
• Abduction: Moving a limb away from the midline of the body (e.g., raising the arm out to the side).
• Adduction: Moving a limb toward the midline of the body (e.g., lowering the arm to the side).
• Internal (Medial) Rotation: Rotating a limb toward the midline (e.g., turning the thigh inward).
• External (Lateral) Rotation: Rotating a limb away from the midline (e.g., turning the thigh outward).
• Circumduction: A combination of flexion, extension, abduction, and adduction, creating a cone-like movement (e.g., rotating the arm in a circle).
• Pronation: Turning the palm downward (forearm) or flattening the arch (foot).
• Supination: Turning the palm upward (forearm) or raising the arch (foot).
• Dorsiflexion: Bending the ankle to bring the top of the foot toward the shin.
• Plantarflexion: Bending the ankle to point the foot downward.

Understanding osteokinematics is fundamental for describing exercises, assessing range of motion, and identifying gross movement limitations.

Type 2: Arthrokinematic Movements

Arthrokinematic movements are the small, involuntary movements that occur between the articular (joint) surfaces within the joint capsule. These subtle motions are essential for allowing full, smooth, and pain-free osteokinematic movement. They are often not consciously controlled and cannot be directly measured with a goniometer.

Key Characteristics of Arthrokinematic Movements:

• Involuntary and Subtlety: These motions are typically unconscious and very small in magnitude.
• Essential for Joint Health: Proper arthrokinematics reduce friction, distribute stress, and prevent excessive wear on joint surfaces.
• Three Primary Types:
  • Roll: New points on one articular surface come into contact with new points on the opposing articular surface. Imagine a car tire rolling on the road.
  • Slide (or Glide): A single point on one articular surface comes into contact with multiple points on the opposing articular surface. Imagine a car tire skidding on ice.
  • Spin: A single point on one articular surface rotates on a single point on the opposing articular surface. Imagine a top spinning in place.

Importance of Arthrokinematics:

Consider the example of knee flexion. As the tibia flexes on the femur (osteokinematic movement), there is a simultaneous posterior roll and posterior glide of the tibia on the femur (arthrokinematic movements). Without the accompanying glide, the tibia would simply roll off the back of the femur, limiting range of motion and potentially causing injury. This intricate dance ensures joint congruency and stability throughout the movement.

The Interplay: Why Both Matter

Osteokinematic and arthrokinematic movements are two sides of the same coin. You cannot have one without the other for optimal joint function.

• Arthrokinematics facilitate Osteokinematics: The precise rolling, sliding, and spinning within the joint capsule are prerequisites for achieving full, unrestricted osteokinematic range of motion. If arthrokinematic motion is impaired (e.g., due to stiffness, adhesions, or swelling), the larger osteokinematic movements will be limited or painful.
• Joint Health and Stability: Proper arthrokinematics distribute forces evenly across the joint surfaces, reducing stress concentration and minimizing wear and tear on cartilage. They are critical for maintaining joint congruency and preventing impingement.
• Rehabilitation and Performance: In physical therapy, techniques like joint mobilizations directly target arthrokinematic movements to restore lost range of motion and reduce pain. For fitness professionals, understanding this interplay helps identify the root cause of movement limitations – is it a muscle flexibility issue (affecting osteokinematics) or a joint capsule restriction (affecting arthrokinematics)?

Practical Applications for Fitness Professionals and Enthusiasts

A comprehensive understanding of both types of joint movement empowers you to:

• Perform Better Assessments: Beyond just measuring osteokinematic ROM, consider if arthrokinematic restrictions are limiting movement. This might involve assessing joint play or end-feel.
• Design More Effective Programs: Incorporate exercises that not only strengthen muscles through osteokinematic movements but also promote healthy arthrokinematics through full, controlled ranges of motion and specific mobility drills.
• Enhance Exercise Technique: Recognize how subtle shifts in joint positioning (affecting arthrokinematics) can impact the efficiency and safety of a lift. For example, maintaining proper scapulohumeral rhythm during overhead movements prevents shoulder impingement.
• Prevent Injuries: By addressing limitations in either type of movement, you can reduce the risk of compensatory patterns and overuse injuries.
• Communicate More Effectively: Use precise terminology when discussing movement with clients or other professionals, demonstrating a deeper understanding of human biomechanics.

Conclusion

The two major types of joint movement, osteokinematics and arthrokinematics, represent the macroscopic and microscopic aspects of how our joints function. While osteokinematics describe the visible movements of our limbs, arthrokinematics describe the crucial, subtle motions occurring within the joint itself that enable smooth and healthy movement. A holistic appreciation of both is fundamental for anyone serious about optimizing human movement, whether in the realm of exercise, rehabilitation, or daily life.