Related Clues:

• They help make joints
• Parts of arms
• They parallel radii
• Soviet military force
• Arms runners?
• Trotsky's force
• They help form joints
• Wrist-to-elbow bones
• Radii companions
• Bodily pair
• Bones in forearms
• Bolshevik fighting force
• Elbow bones
• They're parallel to 28-Across
• Bony neighbors of radii