Aberrant Branches of the Subclavian Artery and their Relationship with the Phrenic Nerve and the Brachial Plexus

Variations in subclavian artery branches are relatively common and may impact surgical procedures and effects. During educational dissection of a male cadaver, we encountered an extremely rare variation of the right subclavian artery branches. The internal thoracic artery, the thyrocervical trunk, and the costocervical trunk arose from the third part of the right subclavian artery. In addition, the phrenic nerve displaced remarkably laterally by the thyrocervical trunk, and the course of the costocervical trunk was between the upper trunk and the middle trunk of the brachial plexus. These variations may pose a potential risk for nerve compression and increase the risk of arterial and nerve puncture. This case report would bring attention to the possibility of other similar cases, and early detection of these variations through diagnostic interventions is helpful to reduce postoperative complications.