Dr. Smith completed an ethmoidectomy. He removed the sinus located ____.

The ethmoidectomy involves the surgical removal of the ethmoid sinuses, which are situated between the eyes. This area consists of several small, air-filled spaces within the bones of the skull, directly connecting to the nasal cavity. The procedure is often performed to treat conditions such as chronic sinusitis, where the ethmoid sinuses become inflamed or infected.

The location of the ethmoid sinuses underscores why option C is accurate. They are specifically located in the region that lies between the orbits of the eyes, making this choice the correct answer to where the sinus is positioned. Other options such as above the eyes, near the nose, and below the forehead do not accurately describe the anatomical position of the ethmoid sinuses.