The dissection of 223 subjects has revealed 3 cases of A. lusoria (1.06%). In all these cases, the A. lusoria was the last branch of the aortic arch. 2. X-ray pictures were taken after injection of radio-opaque substance to elicit the topographical relations of A. lusoria with esophagus. 3. There were only small variations in the calibre and in the way of its branches. Right common carotid artery directly arose from the aortic arch. 4. The three Aa. lusoriae crossed the dorsal face of esophagus between the 4th and 2nd cervical vertebrae where they provoked at neat natch. 5. In one case, there was a marked narrowing at the origin of the artery. In another case, there was an initial widening of the artery. 6. Histological examination of the arterial wall from the portion between oesophagus and vertebral column demonstrated a decrease in number of elastic fibres towards the column. 7. In all cases, there was around A. lusoria a normal Ansa subclavia from the sympathetic trunk. 8. In one case, recurrent nervus were topographically normal on both sides. In both other cases, the right recurrent nerve did not pass under the right subclavian artery but went directly to the larynx without touching the right inferior thyroid artery and its branches.
