Inferior lingular artery of left lung

The inferior lingular artery of the left lung (A5) is a segmental branch of the left pulmonary artery that supplies the inferior lingular segment (S5) of the lingular division of the left upper lobe.

Anatomical definition and course

The left upper lobe is divided into a superior division (apicoposterior and anterior segments) and a lingular division, which comprises two segments: the superior lingular segment (S4) and the inferior lingular segment (S5). The arterial supply to these segments arises from the left pulmonary artery as it courses through the interlobar fissure. The inferior lingular artery (A5) typically originates from the interlobar portion of the left pulmonary artery, either as an independent branch or as part of a common lingular trunk (A4+5) shared with the superior lingular artery (A4).

Branching patterns and variations

Anatomical studies using three-dimensional CT angiography and bronchography have demonstrated considerable variability in the lingular arterial supply:

• A single common lingular trunk (A4+5) is the most frequent interlobar pattern, observed in approximately 38.6% of cases.

• Two separate interlobar arteries (A4 and A5) are found in a substantial proportion of patients.

• In approximately 24% of cases, A5 arises from the basal segmental artery (A8 or A8+9) rather than from the typical interlobar trunk, and in an additional ~8% of cases, the origin of A5 is located in close proximity to A8 or A8+9.

• A mediastinal lingular artery (MLA), originating directly from the proximal left pulmonary artery before it enters the interlobar fissure, is present in approximately 29% of individuals and may supply part or all of the lingular segments, including the inferior lingular territory.