The supreme intercostal artery includes the last cervical intersegmental artery (C7) - angiographic validation of the intersegmental nomenclature proposed by Dorcas Padget in 1954.

In 1954, Dorcas Padget wrote a note that settled the debate over the labeling of the intersegmental arteries (ISAs) and the level of origin of the subclavian artery (SubA), in agreement with earlier observations made by Hochstetter in the rabbit (1890) and Schmeidel in man (1932). In her proposed nomenclature, Padget introduced the name of proatlantal artery and confirmed that the SubA was associated with the sixth ISA rather than the seventh. However, a generally unnoticed consequence of this now widely accepted terminology lays in its incompatibility with the traditional view of the costocervical trunk (CT), regarding in particular the anatomy of the supreme intercostal artery (SIA). If the SubA derives from the sixth cervical ISA (ISA 6), and the CT provides the first and second posterior IAs (ISA 8 and 9), the seventh cervical ISA (ISA 7) then remains unaccounted for. The purpose of this study was to examine Padget's nomenclature in the light of modern angiographic material to identify the missing seventh ISA. Our findings validate the terminology used by Padget, including the addition of a pro-atlantal artery and the identification of the ISA most commonly associated with the SubA as the sixth ISA, but they also emphasize the need to redefine the anatomy of the SIA to incorporate the seventh cervical ISA.