ðɪ ˈeɪtɹɪəl pˈoːɹʃən ɪz ɹˈaʊndᵻd ænd ˈɔːlmoʊst vˈɜːɾɪkəl; ɪɾ ɪz sˈɪtʃuːˌeɪɾᵻd bᵻhˌaɪnd ðə θˈɜːd, fˈoːɹθ, ænd fˈɪfθ ɹˈaɪt kˈɔstəl kˈɑːɹɾɪlɪdʒᵻz ɐbˌaʊt wˈʌn.twˈɛnti fˈaɪv sˌiːˈɛm.
The atrial portion is rounded and almost vertical; it is situated behind the third, fourth, and fifth right costal cartilages about 1.25 cm.