What term refers to the middle region of the thorax?

The term "sternal" refers to the middle region of the thorax because it is specifically associated with the sternum, a flat bone located in the central part of the chest. The sternum serves as an attachment site for the ribs and plays a critical role in protecting the heart and lungs. This anatomical terminology is essential for understanding the layout of the thoracic region, where the sternal area is typically referenced in a variety of medical contexts, such as during physical examinations or when discussing chest-related conditions.

In contrast, other options refer to different anatomical areas: "popliteal" pertains to the back of the knee, "sural" relates to the calf region of the leg, and "tarsal" refers to the bones in the ankle. Each of these terms denotes a specific location in the body that is distinct from the thorax, highlighting the importance of using precise terminology to avoid confusion in anatomy.