Origin
A continuation of the subclavian artery as it passes the lateral border of the first rib
Parts
- First part – the part of the artery superior to the pectoralis minor
- Second part – the part of the artery posterior to the pectoralis minor
- Third part – the part of the artery inferior to the pectoralis minor
1st part has 1 branch, 2nd part has 2 branches, 3rd part has 3 branches
Branches & Course
1st part
- Superior thoracic artery
- Runs anteriorly to supply pectoralis major and minor
2nd part
- Thoracoacromial artery
- Runs over pectoralis minor to pierce clavipectoral fascia and supply the clavicle, deltoid, acromion and pectoralis muscles via its four terminal branches
- Lateral thoracic artery
- Runs laterally along the lower border of pectoralis minor to supply serratus anterior and both pectoralis muscle
- Also supplies breast tissue in females
3rd part
- Subscapular artery
- Largest branch of the axillary artery
- Runs along the posterior wall of axilla
- Thoracodorsal branch supplies serratus anterior
- Gives circumflex scapular artery contributes scapular anastomosis
- Anterior humeral circumflex artery
- Supplies head of humerus
- Anastomoses with posterior circumflex artery around surgical neck
- Posterior humeral circumflex artery
- Passes through the posterior wall of axilla together with the axillary nerve through the quadrangular space
- Supplies deltoid, triceps brachii and glenohumeral joint
Termination
Continues as the brachial artery at the lower border of teres major.
Relations
- Axillary vein lies medial to the artery along its length
- The 2nd part of the axillary artery is the reference for the cords of the brachial plexus, e.g. posterior cord is posterior to the 2nd part of the artery.
Variants
- High origin of the subscapular artery from 2nd part
- Common trunk for subscapular artery and posterior circumflex humeral artery. Can arise from 2nd or 3rd part
- Common trunk for subscapular artery and posterior circumflex humeral artery with the thoracodorsal artery originating directly from the axillary artery
- Common trunk for subscapular artery, posterior circumflex humeral artery and deep brachial artery
- Anomalous high division into radial and ulnar arteries
- Absence of lateral thoracic artery (replaced by lateral perforating branches of the intercostal arteries)
- Alar thoracic artery: supplies the fat, skin and lymph nodes of the axilla