Thoracic Cavity

  • The thoracic cavity (or chest cavity) is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia). The central compartment of the thoracic cavity is the mediastinum.

Potential Spaces:

  • Right Pleural Cavity
  • Left Pleural Cavity
  • Mediastinum
  • Note Cardiac Window

Pleural cavities

  • The pleural cavity is the space that lies between the pleura, the two thin membranes that line and surround the lungs. The pleural cavity contains a small amount of liquid known as pleural fluid, which provides lubrication as the lungs expand and contract during respiration.


  • is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, the trachea, the phrenic and cardiac nerves, the thoracic duct, the thymus and the lymph nodes of the central chest.


  1. Anterior
  2. Posterior
  3. Superior
  4. Inferior


  • The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic.

Cardiac Valves

  • A heart valve normally allows blood to flow in only one direction through the heart. The four valves are commonly represented in a mammalian heart that determines the pathway of blood flow through the heart. A heart valve opens or closes incumbent on differential blood pressure on each side.


  • Reaches peak mass of 35g at puberty
  • Involves thereafter
  • Functions to educate T lymphocytes to recognize self-antigens


  • The pericardium is a thin sac that surrounds your heart. It protects and lubricates your heart and keeps it in place within your chest. Problems can occur when the pericardium becomes enflamed or fills with fluid.


  • The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, as well as assisting in the removal of metabolic wastes. In humans, the heart is located between the lungs, in the middle compartment of the chest.

Great Vessels

  • Great vessels are the large vessels that bring blood to and from the heart. These are: Superior vena cava. Inferior vena cava. Pulmonary arteries.


  • The esophagus is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa. The esophagus runs behind the windpipe (trachea) and heart, and in front of the spine
  • They keep food and secretions from going down the windpipe.
  • The thoracic cavity is divided into three major compartments: two pleural cavities and mediastinum
  • Apex of lung extends above the clavicle and the inferior limit of the lung corresponds to ribs 6,8 and 10
  • The mediastinum is divided into superior and inferior divisions by a plane running from sternal angle to vertebrae TIV/TV

Heart in Situ

Fibrous Pericardium

  • The fibrous pericardium is the most superficial layer of the pericardium. It is made up of dense and loose connective tissue, which acts to protect the heart, anchoring it to the surrounding walls, and preventing it from overfilling with blood.

Middle mediastinum

  • The middle mediastinum is the space occupied by the heart and pericardium
  • The posterior mediastinum contains descending aorta, oesophagus, vagus nerve, the sympathetic chain, thoracic duct, azygos and hemiazygos veins, and paravertebral lymph nodes.


  • The pericardium is a thin sac that surrounds your heart. It protects and lubricates your heart and keeps it in place within your chest. Problems can occur when the pericardium becomes enflamed or fills with fluid.

Pericardial Cavity

  • The pericardial cavity is the potential space formed between the two layers of serous pericardium around the heart. Normally, it contains a small amount of serous fluid that acts to reduce surface tension and lubricate.

Cardiac Tamponade

  • Cardiac tamponade results from the buildup of fluid between the layers of the pericardium. In acute cardiac tamponade, this fluid accumulation occurs quickly, while it happens slowly in subacute cardiac tamponade.

Heart Chambers

  • The heart has four chambers: two atria and two ventricles. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle.

Right atrium

  • The right atrium is one of the four chambers of the heart. The heart is comprised of two atria and two ventricles.
  • Deoxygenated blood enters the right atrium through the inferior and superior vena cava. The right side of the heart then pumps this deoxygenated blood into the pulmonary arteries around the lungs.

Left Atrium

  • The left atrium is one of the four chambers of the heart, located on the left posterior side.
  • Oxygen-rich blood from the lungs enters the left atrium through the pulmonary vein. The blood is then pumped into the left ventricle chamber of the heart through the mitral valve.


  • An auricle is a feature of the anatomy of the heart.
  •  There are two auricles in the heart. Each one is attached to the anterior surface of the outer-walls of the atria (i.e.left and right atria). They look like wrinkled pouch like structures. Their purpose is to increase the capacity of the atrium and also increase the volume of blood that is able to contain.
  • Auricle is also called atrial appendage. It is the ear like conical muscular pouch that arise from each atrium.

Right Ventricle

  • The right ventricle is the chamber within the heart that is responsible for pumping oxygen-depleted blood to the lungs.

Left Ventricle

  • The left ventricle is one of four chambers of the heart. It is located in the bottom left portion of the heart below the left atrium, separated by the mitral valve. As the heart contracts, blood eventually flows back into the left atrium, and then through the mitral valve, whereupon it next enters the left ventricle.

Pectinate Muscles

  • The pectinate muscles (musculi pectinati) are parallel ridges in the walls of the atria of the heart. They are so-called because of their resemblance to the teeth of a comb as in pecten. Behind the crest (crista terminalis) of the right atrium the internal surface is smooth.

Sinus Venarum

  • In the adult, it is incorporated into the wall of the right atrium to form a smooth part called the sinus venarum, also known as the venarum sinus, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis. The sinus venosus also forms the SA node and the coronary sinus.

Crista Terminalis

  • The crista terminalis is generally a smooth-surfaced, thick portion of heart muscle in a crescent shape at the opening into the right atrial appendage. On the external aspect of the right atrium, corresponding to the crista terminalis is a groove, the terminal sulcus or commonly known as sulcus terminalis.

Fossa Ovalis

  • The fossa ovalis is a depression in the right atrium of the heart, at the level of the interatrial septum, the wall between right and left atrium. The fossa ovalis is the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development.

Coronary Sinus

  • The coronary sinus drains into the right atrium, at the coronary sinus orifice, an opening between the inferior vena cava and the right atrioventricular orifice or tricuspid valve.

Trabeculae Carneae

  • The trabeculae carneae (columnae carneae, or meaty ridges), are rounded or irregular muscular columns which project from the inner surface of the right and left ventricle of the heart. These are different from the pectinate muscles, which are present in the atria of the heart.

Papillary Muscles

  • The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction).

Right Coronary Artery

  • In the coronary circulation, the right coronary artery (RCA) is an artery originating above the right cusp of the aortic valve, at the right aortic sinus in the heart. It travels down the right coronary sulcus, towards the crux of the heart

Left Coronary Artery

  • The left coronary artery (abbreviated LCA) is an artery that arises from the aorta above the left cusp of the aortic valve and feeds blood to the left side of the heart. It is also known as the left main coronary artery (abbreviated LMCA) and the left main stem coronary artery (abbreviated LMS).


Great Cardiac Vein

  • The great cardiac vein (left coronary vein) begins at the apex of the heart and ascends along the anterior longitudinal sulcus to the base of the ventricles. It then curves around the left margin of the heart to reach the posterior surface.

Middle Cardiac Vein

  • The middle cardiac vein is a relatively large vein that commences near to the apex of the heart on its inferior surface. It passes superiorly and to the right in the posterior part of the interventricular groove in the company of the posterior interventricular artery.

Anterior Cardiac Vein

  • The anterior cardiac veins (or anterior veins of right ventricle) comprise a variable number of small vessels, usually between two and five, which collect blood from the front of the right ventricle and open into the right atrium; the right marginal vein frequently opens into the right atrium

Subclavian Artery

  • There are two subclavian arteries that supply our arms with blood. The subclavian arteries branch to the vertebral arteries. These carry oxygenated blood up to the brain from the base of the neck. The right subclavian artery is located below the clavicle. It branches off the brachiocephalic trunk.

Internal Thoracic

  • the internal thoracic artery (ITA), previously known as the internal mammary artery (a name still common among surgeons), is an artery that supplies the anterior chest wall and the breasts.

Costocervical Trunk

  • The costocervical trunk is a short artery that is one of three branches of the first part of the subclavian artery. It arises from the back of the subclavian near the medial margin of the scalenus anterior.

Thyrocervical Trunk

  • The thyrocervical trunk is a branch of the subclavian artery arising from the first portion of this vessel, i.e. between the origin of the subclavian artery and the inner border of the scalenus anterior muscle. It is located distally to the vertebral artery and proximally to the costocervical trunk.

Descending Aorta

  • The descending aorta is part of the aorta, the largest artery in the body. The descending aorta begins at the aortic arch and runs down through the chest and abdomen.


  1. Pulmonary VV
  2. The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation.
  3. Superior Vena Cava
  4. n anatomy, a persistent left superior vena cava (PLSVC) is the most common variation of the thoracic venous system, is prevalent in 0.3% of the population, and an embryologic remnant that results from a failure to involute.
  5. 1st posterior Intercostal VV
  6. The 1st posterior intercostal vein, supreme intercostal vein, drains into the brachiocephalic vein or the vertebral vein. The 2nd and 3rd (and often 4th) posterior intercostal veins drain into the superior intercostal vein.
  7. Azygos System of Veins
  8. The azygos system is considered to be the azygos vein located from rib number 2 to rib number 4 while the left part of the body has the hemiazygos vein and the accessory hemiazygos vein as the venous system. A major tributary is the hemiazygos vein, a similar structure on the opposite side of the vertebral column.
  9. Brachiocephalic V
  10. The left and right brachiocephalic veins (or innominate veins) in the upper chest are formed by the union of each corresponding internal jugular vein and subclavian vein. This is at the level of the sternoclavicular joint. The left brachiocephalic vein is usually longer than the right.
  11. Veins of Vertebral Column
  12. Spinal veins. The spinal veins (veins of the medulla spinalis or veins of the spinal cord) are situated in the pia mater and form a minute, tortuous, venous plexus. They emerge chiefly from the median fissures of the medulla spinalis and are largest in the lumbar region.
  13. Inferior Vena Cava
  14. The inferior vena cava (or IVC) is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. Its walls are rigid and it has valves so the blood does not flow down via gravity. It is formed by the joining of the right and the left common iliac veins, usually at the level of the fifth lumbar vertebra.