Introduction:
The course of the branches of the thyrocervical trunk (TT) such as the inferior thyroid artery (ITA), suprascapular artery (SSA), transverse cervical artery (TCA) and ascending cervical artery (ACA) has a range of anatomical variations. The available literature distinguishes between 4 to 9 types of TT variation and its branches.

Aim:
The following paper presents an anatomical variation that was not included in any known classifications.

Case study:
During routine dissection of a body of a 84-year-old woman located in the Department of Anatomy of the University of Warmia and Mazury in Olsztyn, a following course of TT was observed. In the described case the SSA derives directly from the subclavian artery (SA), while the TT gives away ITA, ACA and TCA, which further bifurcates into two dorsal scapular arteries (DSA).

Results and discussion:
The analysis of the described cadaver showed that this anatomical variation of TT cannot be included in any known classification. This indicates, that it is a very rare anatomical variation of the TT.

Conclusions:
Knowledge of the course of the branches of TT has some significant clinical importance, inter alia during endovascular procedures, during which any mistakes may result in serious consequences for the operated patient. The most accurate understanding of the course of TT vessels and the dissemination of knowledge on this subject may reduce the risk of complications after the treatment.