brysthule
The brysthule, also known as the thoracic cavity, is the space within the chest of vertebrates that is enclosed by the ribs, sternum, and diaphragm. It houses vital organs, most notably the heart and lungs. The thoracic cavity is separated from the abdominal cavity below by the diaphragm, a muscular sheet that plays a crucial role in breathing. The lining of the thoracic cavity is a serous membrane called the pleura. Each lung is surrounded by its own pleural sac, which consists of two layers: the parietal pleura, lining the thoracic wall, and the visceral pleura, covering the surface of the lung. Between these layers is the pleural space, containing a small amount of pleural fluid that lubricates the surfaces, allowing the lungs to move smoothly during respiration. The structure of the brysthule provides protection for the delicate internal organs and is essential for the mechanics of breathing. The rib cage acts as a rigid framework, while the intercostal muscles between the ribs assist in expanding and contracting the chest during inhalation and exhalation. The sternum, or breastbone, forms the front of the rib cage, connecting to the ribs via cartilage.