Around the fourth week of fetal development, the upper limb bud arises from a communication between the lateral plate mesoderm and ectoderm. One of the structures that develops from this interaction is the axial trunk, followed by the axillary artery. Like the other branches of the axillary artery, the superior thoracic artery (also known as the supreme thoracic artery and highest thoracic artery) arises from the vascular plexus that is subsequently derived from the developing upper limb bud. The axillary artery and its branches are typically formed by day 41 of fetal development (Rodríguez-Niedenführ et al. 2001; Arora and Sapra 2022).