ostium primum

noun

ostium pri·​mum -ˈprī-məm How to pronounce ostium primum (audio)
: an opening between the two embryonic atria of the heart that exists temporarily at the bottom of the developing interatrial septum and is eventually closed off by this septum and replaced by the ostium secundum

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Cite this Entry

“Ostium primum.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/ostium%20primum. Accessed 23 Apr. 2024.

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