Anatomy study note · Upper limb

Radioulnar joints and interosseous membrane

The proximal and distal radioulnar joints are synovial pivot joints that, together with the interosseous membrane, allow the radius to turn around the ulna in pronation and supination.

Key points

• Both are synovial pivot joints.
• Proximal: anular ligament around the radial head; cavity shared with the elbow.
• Distal: triangular disc separates it from the wrist.
• Pronators: teres + quadratus. Supinators: biceps (strongest) + supinator.
• Nursemaid's elbow = radial head pulled out of the anular ligament.
• Interosseous membrane: radius → ulna force transfer; taut in midprone.
• Joint: from mesenchyme between bone ends.
• Synovial cavity forms in the middle layer.
• Synovial membrane: type A (phagocytic) + type B (secretory) cells.
• Joint surfaces: hyaline cartilage, no perichondrium.

The full note in the atlas also covers

Features · Action · Nerve supply · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 3, PDF pp. 412–419
• Inderbir Singh’s Human Embryology, ch. 10, PDF p. 144
• BRS Cell Biology & Histology, 7th ed., ch. 7, PDF pp. 117–120, 131

More from the upper limb

• Radius
• Rhomboid major
• Rhomboid minor
• Scapula
• Serratus anterior
• Shoulder joint
• Sternoclavicular joint
• Subclavius
• Subscapular nerves
• Subscapularis
• Supinator
• Suprascapular nerve

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