Axillary artery, the continuation of the Subclavian artery, initiates at the lateral border of the first rib and normally ends at the lower border of teres major, where it obtains the name of brachial artery. Variations in the branching pattern of the axillary artery are common. During a routine dissection of a 25-30-year-old man cadaver, based on the classic Grant’s method, in the Department of Anatomy at Zanjan University of Medical Sciences, we observed an unusual branching in the second part of the left axillary artery. In spite of the existence of thoracoacromial trunk, the second part of the axillary artery had a common trunk for lateral thoracic and thoracodorsal arteries. The thoracodorsal artery accompanying the thoracodorsal vein and nerve entered lattissimus dorsi muscle. The axillary artery has the highest rate of rupture and damage after the popliteal artery, and it can get damaged in an attempt to either reduce old shoulder dislocations or remove axillary lymph nodes. Therefore, a full awareness of the axillary artery variations could prove very useful and essential for medical specialists, especially vascular surgeons, orthopedic surgeons, radiologists, and anatomists.