Details
Thoracic cavity with the heart in situ
Here is the specimen of the thoracic cavity with the heart in situ after removing the sternum and the part of costal cartilages.
In this specimen we can see the cut part of the sternum, i.e., the manubrium, both the clavicles, cut part of costal cartilages that form the rib cage that are numbered from 1-7 on either side. We can also see the xiphoid process. Both sternum and the rib cage protects the heart. The heart is visualized in this specimen being situated in the middle mediastinum. The chambers of the heart can also be seen here such as the right atrium, right ventricle and left ventricle. We can also see the pulmonary trunk and aorta arising from the right and left ventricles respectively. We can also see the vessels which supply the heart such as the right coronary artery. The left anterior descending artery (LADA) is also seen here which is the main artery involved in myocardial infarction. The great cardiac vein is seen running along with it.
Thoracic cavity:
It is also called the chest cavity and is enclosed by the ribs, the vertebral column, and the sternum, or breastbone. It surrounds and protects the lungs and the heart. It is separated from the abdominal cavity by a muscular and membranous partition called the diaphragm.
Heart:
The heart is a conical hollow muscular organ situated in the middle mediastinum. It is four chambered and is enclosed by the pericardium. The heart pumps blood to various parts of the body to meet the nutritional requirements.
Sternum:
It is also called the breast bone and forms the anterior median part of the thoracic skeleton. It is a flat bone and is made up of three parts: the manubrium (head), body and xiphoid process/xiphisternum (tail). The angle between the manubrium and the body is called the sternal angle/ angle of Louis and is represented by the manubriosternal joint. It is an important landmark and corresponds to the level of the second costal cartilage and the fourth thoracic vertebra.
Clavicle:
It is the only long bone that is horizontally placed in the body. Popularly called as the beauty bone, it serves as connecting link between the axial and appendicular skeleton. The clavicle aids in transmitting the weight of the upper limb to the sternum.
Costal cartilages:
The costal cartilages are bars of hyaline cartilage that serve as a continuation of the ribs anteriorly. They contribute to the elasticity of the walls of the thorax.
Mediastinum:
The mediastinum is a space in the thoracic cavity in between the lungs. Its most important content is the heart enclosed by the pericardium in the middle mediastinum, i.e., middle part of the inferior mediastinum. Above it lies the superior mediastinum (i.e., above the sternal angle). In front and behind the heart lies the anterior and posterior mediastina respectively.
Right atrium:
Right atrium is the receiving chamber of the heart which receive the blood (deoxygenated) from the whole body by superior and inferior vena cavae. Extension of the right atrium towards the left is called the right auricle whose margins are notched. The right atrium opens into the right ventricle.
Right ventricle:
The right ventricle receives the blood from the right atrium through the tricuspid orifice and send that blood to lungs for oxygenation through the pulmonary trunk.
Left ventricle:
The left ventricle receives the blood from the left atrium through the bicuspid orifice and sends that blood to whole of the body through aorta.
Pulmonary trunk:
The pulmonary trunk is a blood vessel that arises from the right ventricle of the heart. It extends upward, and divides into the right and left pulmonary arteries that convey the deoxygenated blood to the lungs
Aorta:
The aorta is the main and largest artery of the human body. It originates from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes oxygenated blood to all parts of the body through the systemic circulation.
Right coronary artery:
The right coronary artery (RCA) is one of two main coronary vessels that supply the myocardium (the other being the left coronary artery). It arises from the anterior aortic sinus of the ascending aorta and runs in the coronary sulcus (right atrioventricular groove).
Left anterior descending artery (LADA):
It is a branch of the left coronary artery and is also called the anterior interventricular artery. It runs in the anterior interventricular groove accompanied by the great cardiac vein. It is the artery most commonly involved in blockage resulting in myocardial infarction.
Great Cardiac Vein:
It is a largest tributary of the coronary sinus. It first accompanies the anterior interventricular artery and then the left coronary artery to enter the left end of the coronary sinus.
Content partner
