Which of the following terms is spelled incorrectly?

The term spelled incorrectly among the options is "Hysterctomy." The correct spelling is "Hysterectomy," which refers to a surgical procedure for removing the uterus. This term is commonly used in medical contexts, particularly in gynecology.

When examining the other terms: "Sinusitis" is correctly spelled and refers to inflammation of the sinuses; "Arteriosclerosis" correctly describes the thickening and hardening of artery walls, often associated with aging and cardiovascular disease; and "Lymphadenopathy" is also correctly spelled, indicating disease or enlargement of the lymph nodes. Each of these terms is important in the medical field and is spelled accurately, highlighting the specific nature of the conditions they represent.