Describe the location and position of heart in thorax?
Location of the Heart
The heart is located in the thorax, or chest, specifically within the mediastinum. The mediastinum is the central compartment of the thoracic cavity, bordered by the sternum in the front, the spine in the back, and the lungs on either side. The heart occupies the middle and slightly left portion of the mediastinum, known as the middle mediastinum.
Position of the Heart
The heart is positioned obliquely within the mediastinum, meaning it is not perfectly vertical but rather tilted at an angle. It has an apex (pointed tip) that faces downward, forward, and slightly to the left, while the broader base of the heart is directed upward, backward, and to the right.
To provide a more precise description of the heart's position, we can divide the thorax into four quadrants using imaginary lines. The two vertical lines are called midclavicular lines, drawn vertically down from the middle of each clavicle (collarbone). The two horizontal lines are the transpyloric plane (at the level where the stomach outlet meets the duodenum) and the fourth intercostal space (the space between the fourth and fifth ribs).
Based on this division:
1. The apex of the heart is located in the fifth intercostal space, between the midclavicular line and the left anterior axillary line (a vertical line drawn down from the front of the armpit).
2. The right border of the heart extends along the right sternal border, from the third intercostal space (near the level of the second rib) to the sixth intercostal space (near the level of the fifth rib).
3. The left border of the heart follows a more complex path. It starts at the second intercostal space on the right sternal border, crosses to the left of the sternum, and descends to the apex. The left border of the heart typically lies about 2.5 cm (approximately 1 inch) to the left of the midclavicular line at the level of the fifth intercostal space.
The position of the heart can vary slightly from person to person, depending on individual anatomy. In some cases, the heart may be slightly displaced due to conditions like dextrocardia (heart located on the right side) or situs inversus (mirror-image arrangement of organs, where the heart is on the right and the liver on the left).