Axillary Artery

Axillary Artery is main arterial supply to the Upper Limb of the body.

  • Extension – Begins at the lateral border of 1st rib as continuation of Subclavian Artery.
  • Termination – at lower border of Teres major Muscle & continue as Brachial Artery.
  • It is closely related to Brachial Plexus as the cords are named in relation to position relative to this artery. Also, these two structures are enclosed together in a structure called Axillary Sheath.

Axillary Artery

Parts & Relations

Pectoralis minor Muscle crosses in front of Axillary artery, dividing it into 3 parts –

First Part- Superior/ Proximal to the muscle

  1. Anteriorly – Pectoralis Major Muscle, Cephalic Vein crosses the artery
  2. Posteriorly – Serratus Anterior (1st digitation), Medial cord of Brachial Plexus, Long thoracic Nerve
  3. Medially – Axillary Vein
  4. Laterally – Lateral, Posterior cords of Brachial Plexus

Second Part- Posterior/ Deep to the muscle

  1. Anteriorly – Pectoralis major & minor Muscles
  2. Posteriorly – Posterior Cord of Brachial Plexus, Subscapularis Muscle, Shoulder joint
  3. Medially – Medial Cord of Brachial Plexus, Axillary Vein
  4. Laterally – Lateral Cord of Brachial Plexus

Third Part- Inferior/ Distal to the muscle

  1. Anteriorly – Medial Root of Median Nerve
  2. Posteriorly – Radial & Axillary Nerves, Subscapularis & Teres major Muscles
  3. Medially – Axillary Vein, Medial cutaneous Nerve of forearm, Ulnar Nerve
  4. Laterally – Musculocutaneous Nerve

Relations of Axillary artery: A. First Part, B. Second Part, C. Third Part

Branches

It gives total 6 branches (1 from First part, 2 from Second part, 3 from Third part)

First Part-

  1. Superior Thoracic Artery – Arises near Subclavius muscle, supply Subclavius, Pectoralis major & minor, Medial wall of Axilla.

Second Part-

  1. Thoraco-acromial Artery – emerges at upper border of Pectoralis minor, immediately breaks up into terminal branches (Pectoral, deltoid, acromial, clavicular branches)
  2. Lateral Thoracic Artery – emerges and runs along inferior border of Pectoralis minor, supply to Pectoralis muscles, Serratus anterior muscles, also supply breasts on female.

Third Part-

  1. Subscapular Artery – Largest branch among these, runs along lower border of Subscapularis muscle, gives a large branch – Circumflex scapular artery that runs along lateral border of scapula.
  2. Anterior circumflex humeral Artery – passes in front of surgical neck of Humerus, anastomoses with Posterior circumflex humeral Artery to form Arterial Circle, gives od ascending branch to supply head of humerus and shoulder joint.
  3. Posterior circumflex humeral Artery – passes backward the surgical neck of Humerus to form anastomosis. It supplies deltoid muscle and shoulder joint.

Applied Anatomy

Arterial Anastomosis around Scapula – Occurs at 2 places

Around the body of Scapula

  1. Suprascapular Artery (← Thyrocervical trunk ← Subclavian Artery)
  2. Circumflex scapular Artery (← Subscapular Artery ← Axillary Artery)
  3. Deep branch of transverse cervical artery (← Thyrocervical trunk ← Subclavian Artery)

Over acromion Process

  1. Acromial branch of Thoraco-acromial Artery
  2. Acromial branch of Suprascapular Artery
  3. Acromial branch of Posterior circumflex humeral Artery

These anastomosis serves as alternative pathway of circulation in case of block in between 1st part of Subclavian Artery and 3rd part of Axillary Artery

Axillary sheath enclosing the Axillary artery and Brachial Plexus can be used easily to achieve Brachial Plexus Nerve Block. The position of sheath can be verified by felling the pulsation of third part of the Axillary Artery.

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