Caval_opening

Caval opening

Caval opening

The diaphragm. Under surface. (Vena caval foramen labeled near top center, in white region.)

Superior vena cava, inferior vena cava, azygos vein and their tributaries.

Latin foramen venae cavae

Gray's subject #117 406

The caval opening is a hiatus in the diaphragm of humans through which passes the inferior vena cava, the wall of which is adherent to the margins of the opening, and some branches of the right phrenic nerve.

It is located approximately at the level of the eighth thoracic vertebra (T8), and passes through the diaphragm's central tendon.

It is quadrilateral in form, and is placed at the junction of the right and middle leaflets of the central tendon, so that its margins are tendinous.

By being situated in the tendinous part of the diaphragm, it is stretched open every time inspiration occurs.

Since thoracic pressure decreases upon inspiration and draws the caval blood upwards toward the right atrium, increasing the size of the opening allows more blood to return to the heart, maximizing the efficacy of lowered thoracic pressure returning blood to the heart.

External links

Caval+opening+of+diaphragm at eMedicine Dictionary
SUNY Labs 40:08-0101 - "Major Openings in the Diaphragm"

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v • d • e General anatomy of torso

Thorax/ Thoracic cavity	Mediastinum (Superior, Anterior, Middle, Posterior) • Superior thoracic aperture • Inferior thoracic aperture • Triangle of auscultation • Intercostal space • Thoracic plane • Thoracic wall/Thoracic cage - fascia (Pectoral fascia, Clavipectoral fascia, Thoracolumbar fascia) • Chest • Midsternal line

Thoracic diaphragm	openings (Caval opening, Esophageal hiatus, Aortic hiatus, Foramina of Morgagni) • Central tendon • Crus of diaphragm • arcuate ligaments (Lateral, Medial, Median)

Abdomen/ Abdominal cavity	Retroperitoneum • Paracolic gutters • Hepatobiliary triangle anterior abdominal wall (Arcuate line, Linea alba, Tendinous intersection, Linea semilunaris, McBurney's point, Traube's space, Inguinal triangle) • Inguinal canal (Deep inguinal ring, Superficial inguinal ring, Intercrural fibers, Crura of superficial inguinal ring) • Lumbar triangle • regions (Epigastrium, Hypochondrium, Umbilical region, Latus, Hypogastrium, Inguinal region) • planes (Transpyloric plane, Intertubercular plane, Midclavicular line) fascia (Fascia of Camper, Fascia of Scarpa, Transversalis fascia, Renal fascia, Rectus sheath)

Pelvis/ Pelvic cavity	Pelvic floor • Retropubic space fascia (Pelvic fascia, Superior fascia of diaphragm of pelvis, Inferior fascia of diaphragm of pelvis, Fascia of the Obturator internus, Tendinous arch, Iliac fascia, Iliopectineal fascia)

Perineum	Anal triangle (Ischioanal fossa, Pudendal canal, Anococcygeal raphe) Urogenital triangle (Superficial perineal pouch, Deep perineal pouch) Perineal body fascia (Dartos/fascia of perineum/superficial perineal fascia/Fascia of Colles, Perineal membrane/"Inferior fascia of UGD", "Superior fascia of UGD")