Possible Clues:

• Cartilage
• Sinew
• Cartilage (in meat)
• Cartilage in meat
• A stir in the leg makes one tough
• Tough bit in a steak
• Cartilage; chewy piece of meat
• Glister (anag)
• Chewy stuff made from corn for grinding on sides of ledge
• What's left on the plate set girl off!