Arteria Lusoria

Arteria Lusoria (from Latin lusoria, 'playful' or 'tricky') is an anomalous right subclavian artery (ARSA) arising from the distal aortic arch or descending thoracic aorta distal to the left subclavian artery origin, rather than from the right aortic arch as normal. The anomalous vessel courses behind the esophagus (retroesophageal) to reach the right upper extremity. Embryologically, this results from abnormal regression of the right 4th pharyngeal arch artery and persistence of the right 7th cervical intersegmental artery. Incidence: ~0.5-2% of population. Hemodynamics: the anomalous artery may have a narrow origin (diverticulum of Kommerell at aortic takeoff) creating turbulent flow and potential thrombosis risk. Presentation: most patients are ASYMPTOMATIC (incidental finding on imaging). Symptomatic presentations: (1) Dysphagia lusoria—dysphagia to solids due to external compression of esophagus by the retroesophageal artery; more common if artery dilates or has additional compression; (2) Chest/epigastric pain; (3) Rarely, hemorrhage (erosion through esophagus or aorta), though this is extremely rare. Diagnosis: chest X-ray may be normal or show right aortic arch; CT angiography or MRA confirms diagnosis showing anomalous right subclavian artery origin. Imaging differential includes vascular ring, which is a complete ring; ARSA alone forms an incomplete ring. Treatment: conservative management (no intervention) for asymptomatic patients; surgical intervention (subclavian reimplantation or transposition to right carotid, or left-to-right bypass) for symptomatic dysphagia or hemorrhage risk. On boards: Arteria Lusoria is a classic anatomy pearl—always think of it when presented with dysphagia and right aortic arch or anomalous right subclavian artery. It's usually asymptomatic incidental finding but tested for recognition.