What is the purpose of the yoke on an anaesthetic circuit?

• A. A valve controlling gas flow
• B. Where the cylinder is attached to the anaesthetic machine or cylinder manifold
• C. A reservoir bag
• D. A gauge for pressure

Answer: (B)

The yoke is the attachment point for the gas cylinder to the anaesthetic machine or cylinder manifold. It holds the cylinder securely, aligns the valve with the machine’s regulatory pathway, and often incorporates the pin‑index system that helps ensure the correct gas cylinder is connected to the correct inlet, preventing cross-connection of gases. Once the cylinder is seated in the yoke, opening the valve allows gas to flow into the regulator and onward to the breathing system. The yoke itself is not a valve, a reservoir bag, or a pressure gauge, which is why those options aren’t correct.