The majority of dogs in Thailand are Thai native dogs, but their anatomy is rarely recorded. In this study,
we aimed to investigate the anatomical variation of subclavian arteries of dogs in Thailand. We observed 43
cadavers of Thai native dogs compared to 15 cadavers of other breeds during teaching veterinary anatomy.
Four new branching patterns of subclavian arteries were found and named as type Va, Vb/Vd, VIb, and VIIb/
VIId. Type V had had vertebral artery as the first branch, then costocervical and superficial cervical arteries
arose together. Type Vb/Vd, the internal thoracic artery arose opposite either to the costocervical trunk or
the superficial cervical artery while type Va the internal thoracic artery arose after the superficial cervical
artery, but not opposite to the costocervical trunk. VIIb/VIId was described as vertebral artery is the first
branch and then common trunk of costocervical and superficial cervical arteries, the internal thoracic artery
arose opposite either to the costocervical trunk or the superficial cervical artery. These new patterns accounted
for 5.9% of Thai native dogs in this study. From the new patterns, we created the new model that cover all
possible branching patterns of the subclavian artery (26 variations). Notably, the highest frequency of
branching patterns in Thai native dogs was type I (60.5%), specifically type Ib (33.7%), which was also the
major pattern for both sides of subclavian arteries and both sexes of dogs. Type Ib was described as the
vertebral artery was the first branch, then the costocervical trunk, later the superficial cervical and the
internal thoracic arteries arose oppositely. This knowledge is useful for veterinary anatomical education,
physiology, imaging diagnosis, and the surgical treatment for canine thorax, particularly in Thai dogs.