Central tendon of diaphragm
|Central tendon of diaphragm|
The diaphragm. Under surface. (Central tendon visible as large white central arch.)
The thoracic aspect of the diaphragm of a newly born child in which the communication between the peritoneum and pleura has not been closed on the left side; the position of the opening is marked on the right side by the spinocostal hiatus.
|Latin||Centrum tendineum diaphragmatis|
It is inferior to the fibrous pericardium, which fuses with the central tendon of the diaphragm via the pericardiacophrenic ligament.
It is shaped somewhat like a trefoil leaf, consisting of three divisions or leaflets separated from one another by slight indentations.
The right leaflet is the largest, the middle, directed toward the xiphoid process, the next in size, and the left the smallest.
In structure the tendon is composed of several planes of fibers, which intersect one another at various angles and unite into straight or curved bundles—an arrangement which gives it additional strength.
Action during respiration
During respiration the diaphragm contracts causing the central tendon to be drawn inferiorly which partially flattens the domes. The result is an enlargement of thoracic cavity and reduction in intra-thoracic pressure. Physiologically this means that air enters the lungs and venous return to the heart is enhanced. During inspiration the central tendon retains its shape due to its tendinous nature and prevents constriction of the inferior vena cava or aorta, however the esophagus is surrounded by muscle at the esophageal hiatus and is constricted.