Topic Overview

Axillary Artery

Anatomy of Axillary Artery

• Origin → Continuation of subclavian artery at the outer border of 1st rib.

• Termination → Becomes brachial artery at lower border of teres major.

• Course → Lies in axilla, surrounded by cords of brachial plexus.

• Division → Divided into 3 parts by pectoralis minor:

1. First part (proximal to pectoralis minor) → 1 branch

   • Superior thoracic artery.

2. Second part (behind pectoralis minor) → 2 branches

   • Thoracoacromial artery (Clavicular, Acromial, Deltoid, Pectoral branches).

   • Lateral thoracic artery.

3. Third part (distal to pectoralis minor) → 3 branches

   • Subscapular artery (largest branch).

   • Anterior circumflex humeral artery.

   • Posterior circumflex humeral artery.

👉 Mnemonic: “1, 2, 3 rule → Screw The Lawyer, Save A Patient”.

Relations of Axillary Artery

First Part

• Anteriorly → Pectoralis major, clavipectoral fascia.

• Posteriorly → 1st intercostal space, serratus anterior.

• Medially → Axillary vein.

• Laterally → Trunks/cords of brachial plexus (at higher level).

Second Part (behind pectoralis minor)

• Anteriorly → Pectoralis minor, pectoralis major.

• Posteriorly → Posterior cord of brachial plexus, subscapularis.

• Medially → Medial cord of brachial plexus.

• Laterally → Lateral cord of brachial plexus.

Third Part

• Anteriorly → Skin, fascia, pectoralis major, medial root of median nerve.

• Posteriorly → Subscapularis, teres major, latissimus dorsi, axillary nerve, radial nerve.

• Medially → Ulnar nerve, medial cutaneous nerves of arm & forearm, axillary vein.

• Laterally → Lateral root of median nerve, musculocutaneous nerve.

Clinical Anatomy of Axillary Artery

• Compression → Can be compressed against 1st rib in axilla to control bleeding in upper limb.

• Aneurysm → Axillary artery aneurysm may compress brachial plexus → pain, paresthesia, weakness.

• Trauma → Injured in stab wounds or dislocation of shoulder.

• Collateral circulation → Important around scapula; ensures blood supply in case of arterial obstruction.

• Surgical relevance → During axillary clearance (for carcinoma breast), artery is exposed and must be preserved along with surrounding nerves.

• Relations with brachial plexus → Clinical basis for axillary nerve blocks (anesthesia of upper limb)