Welcome to our next lesson on articulations. In our previous session, we built a foundational vocabulary for describing general body movements like flexion, extension, abduction, and adduction. Today, we will expand on that by exploring "special movements"—those that are unique to specific joints and don't neatly fit into the broader categories.
Your goal for this lesson is to define and identify these special movements, including supination/pronation and inversion/eversion. Mastering this terminology is essential for your upcoming exam and is a practical skill you will use constantly as a nurse to accurately describe a patient's mobility, assess nerve function, or document injuries. We will cover movements of the forearm, foot, jaw, and thumb.
Movements of the Forearm: Supination and Pronation
Let's begin with the forearm. The ability to rotate your forearm is crucial for many daily tasks. This movement occurs at the radioulnar joints and is described by two opposing terms: supination and pronation.
- Supination: This is the rotational movement that turns the forearm so the palm faces anteriorly or superiorly. In the anatomical position, the forearms are supinated. A helpful mnemonic is to think of holding a bowl of soup—you can only do this with your palms facing up.
- Pronation: This is the opposite movement, where the forearm rotates so the palm faces posteriorly or inferiorly.
To see these movements in action and hear the "soup" mnemonic explained, let's turn back to Dr. Matt & Dr. Mike.
This short clip from the "Joint Movements" video provides a clear, memorable demonstration of supination and pronation.
Please watch the segment from pronation and supination. Focus on how the hands are oriented in each position.
Anatomically, these movements involve the radius and ulna—the two bones of your forearm. For a more detailed explanation of how these bones interact, the following text is very helpful.
This resource from LibreTexts explains the underlying bone movement during supination and pronation.
Please read the section on Supination and Pronation. Note how the radius crosses over the ulna to form an "X-shape" during pronation, and how they are parallel during supination.
Movements of the Foot: Flexion and Inversion
The foot also has several unique movements that are essential for walking, maintaining balance, and adapting to uneven surfaces. These movements occur at the ankle and the joints between the tarsal bones (intertarsal joints).
Dorsiflexion and Plantar Flexion
These two movements occur at the ankle joint.
- Dorsiflexion: This involves lifting the front of the foot so that the top of your foot (its dorsal surface) moves toward your anterior leg. Think of pulling your toes up towards your shin.
- Plantar Flexion: This is the movement of pointing your toes downward, as if standing on tiptoe or "planting" your foot on the ground.
Watch this quick demonstration to visualize the difference.
This clip from "Joint Movements" clearly illustrates dorsiflexion and plantar flexion at the ankle.
Watch the segment from dorsiflexion and plantar flexion. The mnemonic for plantar flexion is particularly useful.
Inversion and Eversion
These complex movements do not occur at the ankle joint itself, but at the intertarsal joints of the foot.
- Inversion: This is the movement of turning the sole of the foot inward, toward the midline of the body. A hint is to remember inversion turns the foot inward.
- Eversion: This is the opposite, turning the sole of the foot outward, away from the midline.
As a nursing student, understanding these movements is clinically important, especially when assessing for ankle sprains or nerve damage. The following video is made specifically for a nursing audience.
Understanding Body Movements: Key Movements for Nurses – Flexion, Abduction & More
This video from SimpleNursing explains inversion and eversion and notes their clinical relevance.
Watch the clip from inversion and eversion. Pay attention to the simple memory aids ("in for inward" and "e for Evert or outward").
To solidify your understanding of all four foot movements, please review the definitions in the LibreTexts resource.
This text provides clear definitions and highlights the functional importance of these movements.
Read the two short sections on Dorsiflexion and Plantar Flexion and Inversion and Eversion. Note the key distinction that dorsiflexion/plantar flexion are ankle movements, while inversion/eversion involve the intertarsal joints.
Special Movements of the Jaw, Scapula, and Thumb
Finally, let's cover a few more pairs of special movements that occur in other parts of the body.
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Protraction and Retraction: These are anterior-posterior movements.
- Protraction: Moving a body part forward in the horizontal plane (e.g., jutting your chin or pushing your shoulders forward).
- Retraction: The opposite movement, pulling the body part back to the anatomical position or posterior to it (e.g., pulling your chin or shoulders back).
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Elevation and Depression: These are movements in a superior or inferior direction.
- Elevation: Lifting a body part superiorly (e.g., shrugging your shoulders or closing your mouth).
- Depression: Lowering a body part inferiorly (e.g., relaxing your shoulders after a shrug or opening your mouth).
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Opposition and Reposition: These movements are unique to the thumb.
- Opposition: The movement of bringing the tip of your thumb to touch the tip of another finger. This is possible due to the saddle joint at the base of the thumb and is critical for grasping objects.
- Reposition: Returning the thumb to its anatomical position.
The following image provides a fantastic visual summary of all these special movements.
For concise definitions of these final movements, please refer to the following sections in the LibreTexts resource.
This text quickly defines the movements of the mandible, scapula, and thumb.
Please read the following three brief sections: Protraction and Retraction Depression and Elevation Opposition and Reposition
Conclusion
In this lesson, we have defined the key "special movements" that occur at specific synovial joints throughout the body. Unlike the general movements from our last session, these terms describe the unique functional capabilities of the forearm, foot, jaw, and thumb.
Key Takeaways:
- Supination (palm up) and Pronation (palm down) are rotational movements of the forearm.
- Dorsiflexion (toes up) and Plantar Flexion (toes down) are movements of the ankle joint.
- Inversion (sole in) and Eversion (sole out) are movements of the intertarsal joints of the foot.
- Protraction (forward) and Retraction (backward) describe anterior-posterior movements of the mandible or scapula.
- Elevation (up) and Depression (down) describe superior-inferior movements of the mandible or scapula.
- Opposition is the special movement of the thumb touching other fingertips.
Now that you have a comprehensive vocabulary for describing joint motion, our next lessons will apply this knowledge. We will examine the detailed anatomy of the shoulder and knee joints, exploring the specific structures that allow for—and limit—their wide range of movements.