Possible Clues:

• Place on a leash
• Patient finally given anaesthetic -- it'll ensure lack of movement
• Restrain, in a way
• Hold by a rope
• Build station around the chain
• Restrain (an animal) with a rope
• Secure section of route there, else evacuate the road
• Horse restraint
• Allow to move freely? Quite the reverse -- or partly so
• Bird endlessly circling the moor