ABSTRACT
The aorta develops from the 4th branchial arches, the carotid arteries from the 3rd and the pulmonary arteries from the 6th. The aorta initially forms a vascular ring, with bilateral descending aortae. Normally the right descending aorta and the posterior right sided part of the ring atrophy. An aortic vascular ring may cause compression of the trachea and/or oesophagus; many cases presenting in infancy, but some only as adults. In the latter chronic tracheal compression may lead to tracheomalacia, so that surgical correction is usually more successful in children. Venous impression on the oesophagus e.g. the left inferior pulmonary vein may cause an indentation on it about 4 to 5 cm below the level of the carina. A pulmonary arterial ring, pseudo-vascular rings or slings with the left pulmonary artery arising from the right, persistent patent ductus, etc. may also occasionally cause pressure on the oesophagus and dysphagia, as well as dyspnoea.
