Which prefix indicates the thorax or chest?

The prefix that indicates the thorax or chest is "thorac." This term originates from the Greek word "thorax," which specifically refers to the part of the body between the neck and the diaphragm. In medical terminology, prefixes are often used to describe specific body parts or regions, and "thorac" is commonly used in various medical terms related to the chest. For instance, in words like "thoracotomy," which refers to an incision into the thoracic cavity, the prefix clearly signifies a connection to the chest area.

The other prefixes present do not have this specific association with the thorax. "Pus" relates to a thick fluid produced during inflammation and is not anatomically specific. "Rhin" refers to the nose, and "trache" pertains to the trachea, or windpipe. Thus, "thorac" unequivocally designates the thoracic region in medical contexts.