In the upper body there are several different cavities. In the head, humans have the cranial cavity, and just down from that in the chest is the thoracic cavity, which runs from the bottom of the neck down to the end of the ribs, or more accurately at the diaphragm. The rib cages and the thoracic wall may sometimes be called a thoracic cage, but thoracic cavity may be more widely used, especially in the medical field.
There are a number of structures held in the thoracic cavity, and some of the most vital in the human body. The lungs and heart both take residence in this area of the body, and some of the most important vessels that lead in or out of the heart are present here too. These include the aorta, pulmonary artery, and superior and inferior vena cavae.
Structures attached to the lungs are located in this area, including the trachea. Another structure passing through the cavity is the esophagus. Key parts of the endocrine system like the thyroid and thymus glands can be found here too.
Ways exist to further categorize the areas of the thoracic cavity. They may be divided into smaller categories called the pleural cavities, and the mediastinum. The term pleural refers to the membranous lining around the lungs that aids in their function. When people have a pleural effusion they have fluid buildup in this lining.
Mediastinum may be used to describe the middle section of the thoracic cavity which holds most everything but the lungs, including heart, great vessels, esophagus, trachea. To make matters slightly more confusing, mediastinum may be separated into anterior, middle and posterior sections. The average person may never need to know quite this much, but these distinctions are vital when it comes to understanding this section of the body from a medical and surgical perspective.
It might be useful to view the thoracic cavity as thoroughly filled with things vital to the body’s function. There are certain nerves present there too, and any surgery taking place in this area must avoid potentially injuring these, while repairing what is needed. This become easier as people grow because the cavity has grown, providing more space between the structures. Yet, it’s somewhat remarkable to think of surgeons being able to perform things like heart or lung surgery on infants, when the structures inside this cavity are tiny, and the cavity itself is not very large. Exceptional precision is certainly required.