What injection technique involves injecting at one site while draining from another site?

The correct answer is the split injection technique. This method is characterized by the simultaneous injection of embalming fluid at one location while draining fluid from a different site, usually through the venous system. This technique allows for effective distribution of the embalming solution throughout the body, enhancing the embalming process by ensuring that the fluid can circulate effectively and displace blood and other fluids.

Using the split injection method promotes a more uniform distribution of the embalming chemical, helping to prevent issues such as fluid pockets or inadequate preservation, which can occur if fluid is administered in a less strategic manner. The separation of injection and drainage sites also helps to create a better flow of fluid through the vascular system, making the overall process more efficient.

In contrast, the other techniques mentioned either do not involve this dual process of injection and drainage or do so in a different manner that does not achieve the same effectiveness. Understanding the specificity of split injection is crucial for effective embalming practice, as it directly impacts the preservation of the deceased.