Thoracic diaphragm
The thoracic diaphragm, or simply the diaphragm (/ˈdaɪəfræm/;[1] Ancient Greek: διάφραγμα, romanized: diáphragma, lit. 'partition'), is a sheet of internal skeletal muscle[2] in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration,[3] and separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs.[4] Its high oxygen consumption is noted by the many mitochondria and capillaries present; more than in any other skeletal muscle.[3]
This article is about anatomic structure. For other uses, see Diaphragm (disambiguation).Diaphragm
L1-L3, the xyphoid process, 6-12th rib and their costal cartilages
Phrenic and lower intercostal nerves
diaphragma
διάφραγμα
The term diaphragm in anatomy, created by Gerard of Cremona,[5] can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic diaphragm. In humans, the diaphragm is slightly asymmetric—its right half is higher up (superior) to the left half, since the large liver rests beneath the right half of the diaphragm. There is also speculation that the diaphragm is lower on the other side due to heart's presence.
Other mammals have diaphragms, and other vertebrates such as amphibians and reptiles have diaphragm-like structures, but important details of the anatomy may vary, such as the position of the lungs in the thoracic cavity.
Clinical significance[edit]
Paralysis[edit]
If either the phrenic nerve, cervical spine or brainstem is damaged, this will sever the nervous supply to the diaphragm. The most common damage to the phrenic nerve is by bronchial cancer, which usually only affects one side of the diaphragm. Other causes include Guillain–Barré syndrome and systemic lupus erythematosus.[18]
