Chapter 19 - Section 19.1 - Study Guide - Assess Your Learning Outcomes - Page 740: 3

The heart is a muscular organ located in the thoracic cavity, between the lungs, and slightly to the left of the midline of the chest. It is positioned behind the sternum (breastbone) and between the 2nd and 6th ribs. Here are some details about the location, size, and anatomical features of the heart: - **Location**: The heart is situated in the mediastinum, which is the central part of the thoracic cavity between the two pleural cavities (spaces around the lungs). It rests on the diaphragm, the muscular partition that separates the thoracic and abdominal cavities. - **Size**: The size of the heart can vary among individuals, but on average, it is about the size of a closed fist. The dimensions and weight of the heart change with age, fitness level, and various health conditions. - **Base and Apex**: - The **base** of the heart is the broader, superior (upper) portion. It is formed mainly by the atria (right and left atrium) and is located at the level of the 2nd rib. - The **apex** of the heart is the pointed, inferior (lower) portion. It is formed by the left ventricle and is positioned at the 5th intercostal space, about midclavicular line. The apex is palpable at this location and is often used to locate the point of maximal impulse (PMI) during a physical examination. The heart's orientation within the thorax causes the apex to point downward, to the left, and slightly anteriorly. The right side of the heart is generally more anterior, while the left side is more posterior. It's important to note that the heart's position can be influenced by factors such as body position, lung inflation, and individual anatomy. Understanding the heart's location and its relationship to surrounding structures is essential for diagnosing and treating various cardiac conditions.

The heart is a muscular organ located in the thoracic cavity, between the lungs, and slightly to the left of the midline of the chest. It is positioned behind the sternum (breastbone) and between the 2nd and 6th ribs. Here are some details about the location, size, and anatomical features of the heart: - **Location**: The heart is situated in the mediastinum, which is the central part of the thoracic cavity between the two pleural cavities (spaces around the lungs). It rests on the diaphragm, the muscular partition that separates the thoracic and abdominal cavities. - **Size**: The size of the heart can vary among individuals, but on average, it is about the size of a closed fist. The dimensions and weight of the heart change with age, fitness level, and various health conditions. - **Base and Apex**: - The **base** of the heart is the broader, superior (upper) portion. It is formed mainly by the atria (right and left atrium) and is located at the level of the 2nd rib. - The **apex** of the heart is the pointed, inferior (lower) portion. It is formed by the left ventricle and is positioned at the 5th intercostal space, about midclavicular line. The apex is palpable at this location and is often used to locate the point of maximal impulse (PMI) during a physical examination. The heart's orientation within the thorax causes the apex to point downward, to the left, and slightly anteriorly. The right side of the heart is generally more anterior, while the left side is more posterior. It's important to note that the heart's position can be influenced by factors such as body position, lung inflation, and individual anatomy. Understanding the heart's location and its relationship to surrounding structures is essential for diagnosing and treating various cardiac conditions.