Truncus arteriosus
Heart of humanembryo of about twenty-four days. (Truncus arteriosus visible at top.)
Diagrams to illustrate the transformation of thebulbus cordis. Ao.Truncus arteriosus. Au.Atrium. B. Bulbus cordis. RV.Right ventricle. LV.Left ventricle. P.Pulmonary artery.
Details
Precursor	Cardiogenic area
Gives rise to	Aorta,pulmonary artery
System	Cardiovascular system
Identifiers
MeSH	D014338
TE	arteriosus_by_E5.11.1.8.1.0.4 E5.11.1.8.1.0.4
FMA	70301
Anatomical terminology [edit on Wikidata]

Thetruncus arteriosus is a structure that is present during embryonic development.^{[clarification needed]} It is an arterial trunk that originates from both ventricles of the heart that later divides into theaorta and thepulmonary trunk.^[1]

The truncus arteriosus andbulbus cordis are divided by theaorticopulmonary septum. The truncus arteriosus gives rise to the ascendingaorta and thepulmonary trunk. The caudal end of the bulbus cordis gives rise to the smooth parts (outflow tract) of the left and right ventricles (aortic vestibule &conus arteriosus respectively).^[2] The cranial end of the bulbus cordis (also known as the conus cordis) gives rise to the aorta and pulmonary trunk with the truncus arteriosus.

This makes its appearance in three portions.

1. Two distal ridge-like thickenings project into the lumen of the tube: the truncal and bulbar ridges.^[3] These increase in size, and ultimately meet and fuse to form a septum (aorticopulmonary septum), which takes a spiral course toward the proximal end of the truncus arteriosus. It divides the distal part of the truncus into two vessels, theaorta andpulmonary artery, which lie side by side above, but near the heart the pulmonary artery is in front of the aorta.
2. Fourendocardial cushions appear in the proximal part of the truncus arteriosus in the region of the futuresemilunar valves; the manner in which these are related to the aortic septum is described below.
3. Two endocardial thickenings—anterior and posterior—develop in the bulbus cordis and unite to form a short septum; this joins above with the aortic septum and below with the ventricular septum. The septum grows down into the ventricle as an oblique partition, which ultimately blends with the ventricular septum in such a way as to bring the bulbus cordis into communication with the pulmonary artery, and through the latter with the sixth pair ofaortic arches; while the left ventricle is brought into continuity with the aorta, which communicates with the remaining aortic arches.

• 
  Liver with the septum transversum. Human embryo 3 mm. long.
• 
  Illustration of truncus arteriosus in a fully formed heart

Failure of the truncus arteriosus to close results in the condition known aspersistent truncus arteriosus, a rarecongenital heart defect. This is often just referred to astruncus arteriosus.Echocardiography is used to diagnose this condition.^[4][5][6]Other pathologies of the truncus arteriosus includetransposition of the great vessels (arteries in this case), andtetralogy of Fallot.^[7]

This article incorporates text in thepublic domain frompage 514 of the 20th edition ofGray's Anatomy(1918)

• Truncus Arteriosus - Stanford Children's Health
• Embryology at UNSWNotes/heart3b
• Overview at mcgill.ca
• Description and diagram at umich.edu

• Wikipedia articles incorporating text from the 20th edition of Gray's Anatomy (1918)
• Embryology of cardiovascular system

• Articles with short description
• Short description is different from Wikidata
• Wikipedia articles needing clarification from February 2024