The diaphragm is a thin, large musculotendinosus structure inside thorax. It is located just below your lungs, and when relaxed, it has a shape of a dome. It separating the thoracic and abdominal cavities from each other. [1]
The diaphragm consist of 3 parts: sternal, costal and lumbar. The sternal part originates from the posterior aspect of xiphoid process. The costal part arises from the inner surfaces of the cartilages and adjacent parts of the lower sixth ribs on each side. The lumbar part stems from medial and lateral arcuate ligaments, the bodies of vertebrae L1-L3 and their intervertebral discs and anterior longitudinal ligament. [2]
The diaphragm inserts into the central tendon of diaphragm, a structure that is partially connected to the lower surface of the fibrous pericardium. [3]
Due to its location below the lungs, the diaphragm is the backbone of human ability to breathe. It depresses costal cartilages and is the primary muscle in inspiration. As soon as you feel the need for fresh oxygen, it contracts, creating a flat surface. This inhalation action lowers the pressure in your chest, causing your lungs to expand. [4]
Exhaling restores the diaphragm’s original, relaxed shape, which increases the pressure in your chest and causes your lungs to contract again.
- Netter, Frank H. Atlas of Human Anatomy. Sixth edition, Saunders/Elsevier, 2014
- Moore, Keith L., i in. Clinically Oriented Anatomy. 7th edition, Wolters Kluwer/Lippincott Williams & Wilkins Health, 2014
- Sefton, Elizabeth M., i in. „Developmental Origin and Morphogenesis of the Diaphragm, an Essential Mammalian Muscle”. Developmental Biology, t. 440, nr 2, August 2018, s. 64–73. PubMed, https://doi.org/10.1016/j.ydbio.2018.04.010
- Bains, Kanwal Naveen S., i in. „Anatomy, Thorax, Diaphragm”. StatPearls, StatPearls Publishing, 2024. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK519558/