Right inferolateral branch of right coronary artery
Ramus inferolateralis dexter arteriae coronariae dextrae
- Latin synonym: Ramus posterolateralis dexter arteriae coronariae dextrae
- Synonym: Right posterolateral branch of right coronary artery
- Related terms: Right postero-lateral branch
Definition
The right inferolateral branch of right coronary artery (Right posterolateral branch; Posterolateral segmental artery; PLB) of the right coronary artery (RCA) is a terminal branch that arises from the distal continuation of the RCA after the origin of the inferior interventricular artery (posterior descending artery (PDA)), in hearts with right-dominant coronary circulation.
Formal definition and nomenclature
According to the ACC/AHA coronary artery segment classification, in right-dominant circulations the distal RCA bifurcates at or near the crux of the heart into the posterior descending artery (PDA) and the posterolateral segmental artery (PLB; segment 5). From this posterolateral segmental artery, up to three posterolateral branches originate sequentially:
First right posterolateral branch (segment 6)
Second right posterolateral branch (segment 7)
Third right posterolateral branch (segment 8)
Vascular territory
The right posterolateral (inferolateral) branches supply the inferior and inferolateral walls of the left ventricle. In perfusion imaging, the posterolateral artery territory corresponds to the inferolateral segments at the apical level of the left ventricle (AHA 17-segment model). In hearts with a very dominant RCA, these branches can supply nearly half of the left ventricular myocardium, extending the RCA territory well beyond the inferior septum. Proximal RCA lesions in such hearts can therefore be associated with extensive posterolateral ischemia and mitral dysfunction.
Relationship to coronary dominance
The presence of these branches from the RCA defines right coronary dominance, which occurs in approximately 80-90% of individuals. In a right-dominant system, both the PDA and the posterolateral branches (PLA/PLB) arise from the RCA. In left-dominant hearts, these branches instead originate from the left circumflex artery. In co-dominant circulations, the RCA supplies the PDA while the circumflex supplies the posterolateral branches.
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