Final answer:
The provided references do not specify the duration Dr. Carson and Dr. Long took to fashion a new sagittal vein. The information primarily details the embryonic heart development process, including the formation of the heart tube and essential internal structures.
Step-by-step explanation:
The original question seems to refer to a specific surgical procedure where Dr. Carson and Dr. Long had to create a new sagittal vein from pericardium material; however, the reference material provided does not contain information on how long this particular procedure took. The closest related information discusses the development of the heart during embryogenesis, particularly the formation of the heart from the cardiogenic area, development of the endocardial tubes, and the further differentiation into the heart's primary structures. The referenced material points out that the heart starts beating around day 21 or 22, and key structures such as the atrioventricular valves and the semilunar valves form between weeks five and nine.
Regarding the development of the heart's structure, it begins as a primitive heart tube and goes through an S-shaped transformation within the pericardium occurring between days 23 and 28. The heart's internal septa begin to form around day 28, with crucial division of the atria and ventricles. Importantly, the foramen ovale remains open until shortly after birth.