Diaphragm (diaphragma), also known as the midriff, is a muscular partition between the chest cavity and abdominal cavity. It is a thin, wide, unpaired, curved convex side up plate, closing the lower opening of the chest.

In Fig. 107.
Aperture view from above
1 - lumbar portion of the diaphragm;
2 - aortic orifice;
3 - an edge portion of the diaphragm;
4 - esophageal aperture;
5 - opening the vena cava;
6 - tendinous center;
7 - BREAST part of the diaphragm

Diaphragm acts as the main respiratory muscle. Flattening during contraction, it increases the volume of the chest, helping to inhale. Relaxation of the diaphragm takes the spherically convex shape, reduces the chest, which provides an exhalation. With the reduction, together with the abdominal muscles contributes to the work of the diaphragm abdomen.

All of the diaphragm muscle bundles that come from bone and cartilage of the lower aperture of the thorax and lumbar vertebrae are directed to the center where the transferred tendon to tendon bundles and form the center (centrum tendineum) having the form of a trefoil. In the center is a four-tendon hole vena cava (foramen venae cavae), which transmits the inferior vena cava.

In Fig. 108.
Diaphragm and the muscles of the back of the abdominal wall
1 - BREAST part of the diaphragm;
2 - tendinous center;
3 - an edge portion of the diaphragm;
4 - opening the vena cava;
5 - esophageal aperture;
6 - the lumbar portion of the diaphragm;
7 - medial ligament arc;
8 - aortic orifice;
9 - The median arc ligament;
10 - lateral ligament arc;
11 - left leg aperture;
12 - right leg aperture

As the starting point of muscle bundles in the diaphragm are three parts. The belly part (pars sternalis diaphragmatis) starts from the back of the xiphoid process. Ribs (pars costalis diaphragmatis), the most extensive. It starts on the inner surface of the bone and cartilage parts of the lower six ribs. Its beams are directed upwards and inwards. The lumbar portion (pars lumbalis diaphragmatis) is divided into the right leg (crus dextrum) and the left leg (crus sinistrum), each of which starts from the anterolateral surface of the I-III lumbar spine and tendon poyasnichnorebernyh ligaments. The medial ligament arc (lig. arcuatum mediale) goes from body to transverse process I lumbar vertebra, the lateral ligament arc (lig. arcuatum laterale) - from the transverse process of lumbar vertebrae I to XII rib midline Arc ligament (lig. arcuatum medianum) closes the aortic orifice. The central muscle bundles restrict lumbar aortic opening (hiatus aorticus), which transmits the aorta. Is somewhat lower esophageal opening (hiatus esophageus), transmits the esophagus.

Thoracic and abdominal surface of the diaphragm are covered with fascia.

List of Abbreviations

a., aa. — arteria, arteriae (artery, the artery)

lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)

m., mm. — musculus, musculi (muscle, the muscle)

n., nn. — nervus, nervi (nerve, the nerve)

r., rr. — ramus, rami (branch)

s. — seu (or)

v., vv. — vena, venae (vienna)