Variations in the subclavian-axillary arterial system

OBJECTIVE: The objective of this study is to report on the subclavian axillary arterial system variations observed in the dissecting room.

METHODS: The morphological study of 106 formalin fixed upper limbs of adult human cadavers of both sexes was carried out at human anatomy laboratory of College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia over a 5 year period, to observe the distribution pattern of the subclavian axillary arterial system.

RESULTS: The arterial variations in the upper extremities are quite common and may occur at the level of the thoracic outlet, axilla, arm, cubital fossa and the hand. In the present study, the anomalous topographic pattern of the subclavian axillary arterial system was revealed in 7.5% of the cadavers, whereas 92.5% exhibited classical pattern of the regional arterial anatomy. The study showed: 1. An aberrant right subclavian artery arising from the arch of aorta, distal to the left subclavian artery. 2. A bilateral common subscapular-circumflex humeral trunk (3.8%) emerging from the 3rd part of the axillary artery (branching into the circumflex humeral and thoracodorsal arteries. 3. A bilateral thoracohumeral trunk arising from the 2nd part of the axillary artery (1.9%) and branching into the lateral thoracic, circumflex humeral, subscapular and thoracodorsal arteries. These anomalies were accompanied by anomalous insertion of flexor digitorum superficialis muscle, a bilateral digastric muscle formed by the abductor pollicis longus and brevis, and an anomalous formation of median nerve by 3 roots.

CONCLUSION: The aberrant right subclavian artery associated with right non-recurrent laryngeal nerve and variant branching pattern of the axillary artery are of interest to anatomists, surgeons and radiologists and suggested that these anomalies must be evaluated pre-operatively.