The chest cavity is situated between neck and abdomen and starts at the level of collar bones on both sides and ends at diaphragm, the lining that separates chest and the abdomen cavity. As it houses vital structures, it is protected by bony cage all around, namely " the vertebral column at the back, 12 pair of ribs on each side and breast bone (Sternum) in the front. These bony structures prevent injury to inside organs.
The two lungs are situated on either side of the chest cavity. In the middle of the chest is an area called mediastinum which is divided into anterior, middle and posterior parts. The anterior part is anterior to the heart and behind the breast bone and has THYMUS gland and Lymph Nodes.
The middle part of mediastinum has the heart and its great vessels and also the trachea and bronchi (wind-pipe) and esophagus (food-pipe). The posterior part of mediastinum is behind the heart (on either side of the vertebral column) and has various nerves and vessels passing through it.
Our lungs are balloon like structures which expand and collapse with each breath. When we breathe in, the movement of our ribs creates negative pressure in the chest which pulls air from outside into the lungs. When we breathe out, the ribs go back to their original position, creating positive pressure inside the chest which forces the air out of the lungs. This process goes on 12-16 times a minute throughout our life, allowing oxygen to move from inhaled air into blood and CO2 to move out from blood into the exhaled air.
The trachea and bronchi are conduits through which the air entering through our nose reaches up-to the lungs.
The Chest Wall: what role does it play?
The Chest Wall (12 pair of ribs on either side and the breast bone in the middle) protect the vital organs inside the chest from external forces. It is the Movement of the chest wall and diaphragm which creates the pressure changes required for lung expansion.
Diaphragm is a muscular layer that separates the chest cavity from abdomen. It is fixed to the under surface of the heart in the mid-line but on either side, it moves up and down along with the chest wall movement and has major contribution in the pressure changes that occur within the chest leading to the movement of the lungs.
Esophagus (Food Pipe)
It is the conduit through which the chewed food from our mouth passes through the chest and reaches stomach in our abdomen for digestion and other actions.
It is a thin lining which covers the lungs as well as inside of the chest wall. It releases small amount of fluid which lubricates the lung surface, facilitating its movement.
Copyright @ (Prof.) Dr. Arvind Kumar. All Rights Reserved / Thoracic Surgical Oncologis
License Number: U.P State Medical Council (India) No. 27637