This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oesophagus, Subject name: Surgery
Dysphagia lusoria is due to: 
Select and explain. 
A. Esophageal diverticulum, B. Aneurysm of aorta, C. Esophageal web, D. Compression by aberrant blood vessel
D: Compression by aberrant blood vessel
Answer: D: Compression by aberrant blood vessel 
Explanation: Ans. (d) Compression by aberrant blood vesselsRef: Sabiston 19th Edition, Pages 1036-1037* Abnormal origin of right subclavian artery from descending aorta causes dysphagia - known as dysphagia lusoria* The esophagus is compressed posteriorly in this scenario* This type of compression forms a complete ring* Only symptomatic cases need surgerySimilarly pulmonary artery can form Sling and cause dysphagia.* Pulmonary sling causes anterior compression* Pulmonary Sling means Left Pulmonary artery arises from Right PA instead of arising from trunk as shown in figure.* Pulmonary sling always need surgery