Anatomy of the Arm & Hand — Part 7 | Radial-Ulnar Joint & Biceps Function Explained

Описание: In this lesson, we explore the radial-ulnar joint, its movements, and the key muscles that act on it. Understanding this anatomy helps in safe hand and forearm placement in yoga and ensures efficient activation of the biceps.

🔄 Radial-Ulnar Joint

• The radial-ulnar joint allows the forearm to:
– Pronate (palm faces down)
– Supinate (palm faces up)

• This rotation is essential for many daily movements and yoga poses involving weight-bearing on the hands or arm transitions.

💪 Key Muscles Acting on the Radial-Ulnar Joint

Biceps Brachii
• Acts as a supinator of the forearm
• Also flexes the elbow
• Attaches to the radius, allowing it to rotate the palm upwards

Pronator Muscles
• Act to pronate the forearm
• Self-palpation exercises are available in the Google Classroom for 200-hour YTT students

🔍 Biceps Contraction Explained

Have you noticed the typical “bicep curl pose” in anatomy illustrations?

Right elbow flexed + forearm supinated (palm up, across the body) → fullest contraction of the biceps ✅

Right elbow flexed + forearm pronated (palm down) → only partial contraction ❌

Why?

The biceps has two simultaneous actions:

Flexes the elbow

Supinates the forearm (turns the palm up)

When both actions happen together, the biceps bulges maximally and functions most effectively.

📝 Activity for 200-Hour YTT Students

Biceps Brachii Mobilization Exercise:

Flex the elbow

Supinate the forearm

Observe and feel the full contraction of the biceps

Assignment: Complete the activity, experience both actions, and upload your results to the Google Classroom for marking.

💡 Key Takeaways

Full biceps contraction requires simultaneous elbow flexion and forearm supination

Understanding this is important for safe weight-bearing, arm alignment, and functional activation in yoga

Radial-ulnar joint mobility is essential for efficient arm movement in both daily life and asana practiceAnatomy of the Arm & Hand | Radial-Ulnar Joint & Biceps Function Explained