Embryological Basis And Clinical Importance of the Variant Branching Pattern of the Axillary Artery

The arterial pattern of the upper limb is one of the systems that display many variations in the adult human body. Accurate information regarding these variations is important during vascular & reconstructive surgery and also in evaluation of angiographic images. Axillary artery is the direct continuation of the subclavian artery from the outer border of the first rib. The course of the axillary artery is anatomically divided into three parts by the pectoralis minor muscle. The variant case was found during the routine dissection classes in the Department of Anatomy at LLRM Medical College on a 40-year old formalin fixed female cadaver. Axilla was carefully dissected and axillary artery and its branches were cleared & documented. There was unilateral variation in the branching pattern of the first and second part of the axillary artery on right side. From the first part of axillary artery arose two superior thoracic arteries. From the second part of axillary artery arose a common trunk for thoracoacromial, lateral thoracic and subscapular arteries. The common trunk first gave origin to thoracoacromial and subscapular artery. Subscapular artery in turn branched into lateral thoracic and circumflex scapular and then continued as thoracodorsal artery. The left axillary artery exhibited the normal branching pattern. Arterial anomalies in the upper limb are due to defects in embryonic development of the vascular plexus of upper limb bud.