Axillary Artery Anatomy and Relations Quiz

Axillary Artery

• The axillary artery begins at the outer border of the first rib as a continuation of the subclavian artery.
• It enters the axilla through its apex and runs downwards and laterally along the lateral wall of the axilla.
• The axillary artery passes deep to the pectoralis minor muscle, dividing it into three parts:
  • First part: Above the pectoralis minor
  • Second part: Deep to the pectoralis minor
  • Third part (the longest part): Below the pectoralis minor
• The axillary artery ends at the lower border of the teres major muscle (lower limit of the axilla) where it becomes the brachial artery.

Relations

• First part:

  • Medially: Axillary vein
  • Laterally: Lateral and posterior cords of brachial plexus
  • Anteriorly: Anterior wall of axilla
  • Posteriorly: Medial cord of brachial plexus and medial wall of axilla

• Second part:

  • Anteriorly: Pectoralis major and minor muscles
  • Posteriorly:
    • Posterior cord of brachial plexus
    • Subscapularis muscle
  • Medially:
    • Medial cord of brachial plexus
    • Axillary vein
  • Laterally:
    • Lateral cord
    • Coraco-brachialis muscle

• Third part:

  • Anteriorly:
    • Medial root of median nerve crossing from medial to lateral.
    • Pectoralis major muscle
    • The lowermost part of the axillary artery becomes superficial (only covered by skin and fascia) below the lower border of pectoralis major.
  • Posteriorly:
    • Radial and axillary nerves
    • The posterior wall of axilla: subscapularis, teres major and latissimus dorsi (from above downwards).
  • Laterally:
    • Branches of the lateral cord and median nerve.
  • Medially:
    • Branches of the medial cord and axillary vein.

Branches of the Axillary Artery

• First part:

  • Superior thoracic artery: Arises at the lower border of the subclavius muscle, supplying it and anastomosing with the intercostal arteries.

• Second part:

  • Thoraco-acromial artery:
    • A short trunk arising behind the upper border of pectoralis minor.
    • Pierces the clavi-pectoral fascia.
    • Ends by dividing into four branches:
      • Acromial branch: Runs towards the acromion.
      • Pectoral branch (the largest branch): Descends between the two pectoral muscles supplying them and the breast.
      • Clavicular branch: Supplies the subclavius muscle and the sterno-clavicular joint.
      • Deltoid branch: Passes in the deltopectoral groove and supplies the deltoid and pectoralis major muscle.
  • Lateral thoracic artery:
    • Arises behind the lower border of pectoralis minor.
    • Runs along the lower border of pectoralis minor to reach the side of the chest.
    • Supplies the serratus anterior, the pectoral muscles and subscapularis.
    • In females, it is large and gives lateral mammary branches supplying the lateral part of the gland.

• Third part:

  • Subscapular artery (the largest branch):
    • Arises at the lower border of the subscapularis muscle.
    • Gives off a large branch called the circumflex scapular artery.
    • Continues as the thoraco-dorsal artery, supplying the latissimus muscle.
    • Takes part in the anastomosis around the scapula.
  • Circumflex scapular artery:
    • Usually larger than the continuation of the subscapular artery (the thoraco-dorsal artery).
    • Curves around the lateral border of the scapula traversing the upper triangular space.
    • Shares in the anastomosis around the scapula.
  • Anterior circumflex humeral artery (a very small artery):
    • Arises at the lower border of the subscapularis muscle.
    • Runs in front of the surgical neck of humerus.
    • Gives off an ascending branch to supply the shoulder joint and ends by anastomosing with the posterior circumflex humeral artery.
  • Posterior circumflex humeral artery:
    • Supplies the surgical neck and posterior aspect of the humerus.
    • Shares in the anastomosis around the scapula.

Test your knowledge on the anatomy of the axillary artery and its relationships within the axilla. This quiz covers the artery's origins, parts, and its connections with other anatomical structures. Dive deep into vascular anatomy and understand the significance of the axillary artery.