In cardiovascular embryology, the truncus arteriosus is divided into the aorta and pulmonary trunk by the aorticopulmonary septum, which is derived from:

• A Splanchnic lateral plate mesoderm
• B Secondary heart field cells from the pharyngeal mesoderm
• C Proepicardium
• D Cardiac neural crest cells (vagal crest from rhombomeres 6–8) ✓

Explanation

The aorticopulmonary (conotruncal) septum dividing the truncus arteriosus into the ascending aorta and pulmonary trunk is derived from cardiac neural crest cells, specifically from rhombomeres 6–8 (vagal crest). This is why 22q11.2 deletion (TBX1 mutation affecting neural crest migration) causes conotruncal defects such as persistent truncus arteriosus, tetralogy of Fallot, and interrupted aortic arch. The secondary heart field gives rise to the right ventricle and outflow tract myocardium. The proepicardium forms the epicardium and coronary vasculature.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.