[TA] the longer of the two terminal branches of the pulmonary trunk, it passes transversely across the midline in the superior mediastinum, passing inferior to the aortic arch to enter the hilum of the right lung as part of its root. Branches divide and are distributed with the segmental and subsegmental bronchi; frequent variations occur. Typical branches: of the superior lobar arteries [TA] (arteriae lobares superiores pulmonis [TA]) are the apical segmental artery [TA] (arteria segmentalis apicalis pulmonis [TA]), anterior segmental artery (arteria segmentalis anterior pulmonis [TA]) and posterior segmental artery [TA] (arteria segmentalis posterior pulmonis [TA]), with the latter two having ascending and descending branches [TA] (rami ascendens et descendens [TA]); of the middle lobar artery [TA] (arteria lobaris media [TA]) are the medial segmental artery [TA] (arteria lobaris media pulmonis [TA]) and lateral segmental artery [TA] (arteria segmentalis lateralis pulmonis [TA]); and of the inferior lobar arteries [TA] (arteriae lobares inferiores pulmonis [TA]) are the superior segmental artery [TA] (arteria segmentalis superior pulmonis [TA]) and a basal part [TA] (pars basalis [TA]) giving rise to anterior, posterior, lateral, and medial basal segmental arteries [TA] (arteriae segmentales basales anterior, posterior, lateralis et medialis pulmonales [TA]). SYN: arteria pulmonalis dextra [TA].