"subtype 1"
"subtype 2"
"subtype 3the atretic segment lies between the left common carotid and left subclavian arteries"
"subtype 4the atretic zone is proximal to the left common carotid artery"
"There are four subtypes of double aortic arch with left arch atresia according to the Shuford and Sybers classification 1,4:"