In medical terminology, what does "sinus/o" signify?

The term "sinus/o" is derived from the Latin word for "cavity" or "hollow," and in medical terminology, it specifically refers to a sinus. Sinuses are air-filled spaces located within the bones of the skull, which connect to the nasal cavity and play an important role in respiratory function, including lightening the weight of the skull, humidifying inhaled air, and enhancing voice resonance.

Using "sinus/o" in medical terms indicates a relation to these cavities, such as in the words "sinusitis" (inflammation of the sinuses) and "sinusography" (imaging of the sinuses). Understanding this root is essential for recognizing and interpreting various medical terms associated with sinus conditions and procedures.

In contrast, the other options refer to entirely different anatomical structures: "nerve" pertains to the nervous system, "blood vessel" relates to circulatory anatomy, and "muscle" refers to muscular tissue, none of which have a connection to the concept of a sinus. Therefore, the correctness of the choice pointing to "sinus" is solidified by its direct association with the term "sinus/o."