What are supination and pronation?

Supination and pronation are rotatory movements of the forearm that enable skilled hand actions. In the midprone position, supination turns the palm upward (like holding a bowl), while pronation turns the palm downward.

What is the axis of rotation for supination and pronation?

The axis is oblique and vertical, extending from the center of the head of the radius (above) to the base of the ulnar styloid process (below). It shifts forward and medially during supination, and moves backward and laterally during pronation.

How do supination and pronation occur mechanically?

Movement occurs at both the superior and inferior radio-ulnar joints. In supination, the radius and ulna lie parallel. In pronation, the radius rotates over the ulna, with the distal radius crossing in front of the ulna.

Which muscles are involved in supination?

The main muscles for supination are the supinator, biceps brachii (especially when the elbow is flexed), and brachioradialis (from pronated to midprone).

Which muscles are involved in pronation?

The main muscles for pronation are pronator teres, pronator quadratus, and brachioradialis (from supinated to midprone). It is also assisted by flexor carpi radialis, palmaris longus, and gravity.

What are the key functional differences between supination and pronation?

Supination is more powerful, an antigravity movement used for tightening screws and evolved for bringing food to the mouth. Pronation is used for loosening or opening and evolved for picking up food.

Where do supination and pronation movements take place in the joints?

These movements occur at both the superior radio-ulnar joint and the inferior radio-ulnar joint. The head of the radius rotates inside the annular ligament and radial notch of the ulna during these actions.

Supination & Pronation – Forearm Rotation Explained

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