Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 82

The heart has a relatively central position within the thoracic cavity (Figure 3.1) with the bulk of its structure found behind the sternum (breastbone). On average, an adult human heart weighs around 250–350 g and is around 12–14 cm long and 9–11 cm wide. There is much variation in heart size, with larger people unsurprisingly having larger hearts compared to their smaller counterparts. It is commonly stated that an individual’s own heart is roughly the same size as their own clenched fist.

The heart is located in the mediastinum (region between the right and left lung) and is positioned obliquely between the second rib and the fifth intercostal space.

In individuals with a normal body mass index (BMI), the apex heartbeat can usually be detected in the left fifth intercostal space around 8 cm to the left of the central point of the sternum.