Axillary artery

• • Continuation of third part of subclavian artery

• Commencement: Outer border of 1st rib

• Course: Enters apex of axilla passing over first digitation of serratus anterior, behind midpoint of clavicle. At lower border of teres major, it becomes the brachial artery.

• Divided into 3 parts by pectoralis minor, which crosses in front of it

• First part

  • One branch:
    • Superior Thoracic Artery
      • Runs forwards to supply both pectoral muscles

• Second part

  • Two branches:
    • Thoracoacromial Artery
      • Skirts upper border of pectoralis minor ⇒ Pierce clavipectoral fascia – often separately by its 4 terminal branches – clavicular, deltoid, acromial and pectoral ⇒ Branches radiate away at right angles from each other in their respective directions
    • Lateral thoracic artery
      • Follows lower border of pectoralis minor ⇒ supplies branches to pectoralis and serratus anterior muscles
      • In female: important contributor to blood supply of breast

• Third part

  • Three branches:
    • Subscapular artery
      • Largest branch – runs down posterior axillary wall ⇒ Gives off a dorsal branch – the Circumflex Scapular Artery which passes through posterior axilla wall between subscapularis and teres major, medial to long head of triceps and curves backwards round the lateral scapular border
      • Distal to this large branch, the Subscapular Artery changes name to Thoracodorsal Artery⇒ Runs with nerve of same name into Latissimus Dorsi after giving 1-3 branches to Serratus Anterior
      • Latter branches anastomose with Posterior Intercostal Arteries – thus, alternative source of blood supply to latissimus dorsi if subscapular or thoracodorsal artery has been occluded/divided higher up in axilla
      • Thoracodorsal Nerve descends to lie anterior to the artery in a neurovascular bundle that enters latissimus dorsi close to its anterior edge.
    • Anterior Circumflex Humeral Artery
      • Runs deep to coracobrachialis and both heads of biceps
      • Gives off ascending branch that runs up intertubercular sulcus and is an important blood supply to the humeral head
      • Passes around surgical neck of humerus to anastomose with posterior circumflex humeral artery
    • Posterior Circumflex Humeral Artery
      • Passes through quadrangular space in posterior axillary wall, i.e. between subscapularis and teres major, lateral to long head of triceps and medial to the humerus
      • Accompanied above by axillary nerve
      • Supplies deltoid
      • Gives branches to long and lateral heads of triceps and shoulder joint
      • Anastomoses with profunda brachii artery

• Axillary vein lies anteromedial to all parts of the artery

• If arm at the side – artery has bold curve with convexity lateral. If arm abducted and externally rotated, e.g. during surgery, artery has straight course

• Surface marking: A line from the middle of the clavicle to the groove behind coracobrachialis

• Surgical approach: transverse incision below clavicle (pectoralis major split in line of its fibres) OR an incision along the deltopectoral groove (pectoralis major retracted away from deltoid) Tendon of pectoralis minor divided. Cords of brachial plexus and their branches safe guarded