What instrument is inserted into the artery for the introduction of fluid?

The arterial tube is specifically designed to be inserted into the artery for the purpose of introducing embalming fluid during the embalming process. This instrument allows for the effective distribution of the preservative solution throughout the body, ensuring proper preservation and preparation for the final disposition.

The arterial tube typically features a series of openings that facilitate fluid flow, and it's designed to connect to the pump of the embalming machine. Its structure and function are tailored for this critical task, making it the most appropriate choice for fluid introduction during embalming.

In contrast, the other instruments mentioned serve different purposes. A cannula is a generic term for a tube that can be used in various medical situations, including introducing fluids but is not specialized for embalming. A needle injector is used to secure cords and wires within the body, typically in the context of anatomical restoration, rather than fluid introduction. A trocar is used for aspiration and the introduction of fluids into cavities, not specifically for arteries, and its function does not align with the goal of fluid introduction into the arterial system used during embalming.