Vascular Anatomy of the Upper Limb

Origins of Upper Limb Vascular Supply

• The Subclavian Artery

  • Right Subclavian Artery: Originates from the brachiocephalic artery (brachiocephalic trunk).

  • Left Subclavian Artery: Originates directly from the arch of the aorta.

  • Termination: The subclavian artery continues as the axillary artery once it crosses the lateral border of the $1^{st}$ rib.

The Axillary Artery

• Definition and Course

  • Begins at the lateral border of the $1^{st}$ rib as a continuation of the subclavian artery.

  • Continues as the brachial artery at the lower border of the teres major muscle.

  • It is enclosed within the axillary sheath.

  • It is closely related to the cords and branches of the brachial plexus.

• Divisions and Topography

  • The artery is divided into three parts based on its relationship to the pectoralis minor muscle, which crosses over it anteriorly.

  • The $1^{st}$ Part:

    • Extends from the lateral border of the $1^{st}$ rib to the upper border of the pectoralis minor.

    • Relation (Anterior): Pectoralis major muscle.

    • Relation (Lateral): Cords of the brachial plexus.

    • Branches: Gives off ONE branch, the highest thoracic artery.

  • The $2^{nd}$ Part:

    • Lies directly behind the pectoralis minor muscle.

    • Relations: Related medially, laterally, and posteriorly to the corresponding cords (medial, lateral, and posterior) of the brachial plexus.

    • Branches: Gives off TWO branches:

      • Thoracoacromial artery.

      • Lateral thoracic artery.

  • The $3^{rd}$ Part:

    • Extends from the lower border of the pectoralis minor muscle to the lower border of the teres major muscle.

    • Relations: Related medially, laterally, and posteriorly to the branches of the cords of the brachial plexus.

    • Branches: Gives off THREE branches:

      • Subscapular artery.

      • Anterior circumflex humeral artery.

      • Posterior circumflex humeral artery.

Anastomosis Around the Shoulder Joint

• Anastomotic connections occur between branches of the subclavian and axillary arteries to ensure collateral circulation.

• Branches from the Subclavian Artery:

  • Suprascapular artery.

  • Superficial cervical artery.

  • Deep branch of the transverse cervical artery.

  • Thyrocervical trunk (source of the above branches).

• Branches from the Axillary Artery:

  • Subscapular artery.

  • Anterior circumflex humeral artery.

  • Posterior circumflex humeral artery.

  • Circumflex scapular artery (branch of subscapular).

The Brachial Artery

• Overview

  • A continuation of the axillary artery starting at the lower border of the teres major muscle.

  • Main arterial supply for the arm.

  • Termination: Divides into the radial and ulnar arteries opposite the neck of the radius in the cubital fossa.

• Relations

  • Anteriorly: Crossed from above downward by the medial cutaneous nerve of the forearm, the median nerve, and the bicipital aponeurosis.

  • Posteriorly: Relates to the triceps, coracobrachialis, and brachialis muscles.

  • Medially: Basilic vein, ulnar nerve, and median nerve.

  • Laterally: Coracobrachialis and biceps muscles.

• Branches

  • Muscular branches.

  • Nutrient artery to the humerus.

  • Profunda brachii artery (Deep artery of the arm).

  • Superior ulnar collateral artery.

  • Inferior ulnar collateral artery.

Arteries of the Forearm: Ulnar and Radial

• The Ulnar Artery

  • The larger of the two terminal branches of the brachial artery.

  • Begins in the cubital fossa at the level of the neck of the radius.

  • Descends through the anterior compartment of the forearm.

  • Enters the palm in front of the flexor retinaculum, accompanied by the ulnar nerve.

  • Termination: Forms the superficial palmar arch by anastomosing with the superficial palmar branch of the radial artery.

  • Branches:

    • Muscular branches.

    • Recurrent branch (for elbow anastomosis).

    • Common interosseous artery (gives rise to anterior and posterior interosseous arteries).

    • Branch for the wrist joint anastomosis.

• The Radial Artery

  • The smaller terminal branch of the brachial artery.

  • Begins in the cubital fossa at the level of the neck of the radius.

  • Descends downward and laterally.

  • Leaves the forearm by winding around the lateral aspect of the wrist to reach the dorsum of the hand.

  • Branches:

    • Muscular branches.

    • Recurrent branch (for elbow anastomosis).

    • Superficial palmar branch (assists in forming the superficial palmar arch).

Anastomosis Around the Elbow Joint

• Collateral circulation around the elbow involves branches from the brachial, radial, and ulnar arteries.

• From Brachial Artery:

  • Profunda brachii artery (providing radial collateral and middle collateral branches).

  • Superior ulnar collateral artery.

  • Inferior ulnar collateral artery.

• From Ulnar and Radial Arteries:

  • Radial recurrent artery.

  • Anterior ulnar recurrent artery.

  • Posterior ulnar recurrent artery.

  • Interosseous recurrent artery (from posterior interosseous).

Arteries of the Hand and Palmar Arches

• Radial Artery in the Hand

  • Enters the palm by turning forward between the proximal ends of the $1^{st}$ and $2^{nd}$ metacarpal bones and the two heads of the $1^{st}$ dorsal interosseous muscle.

  • Continues as the deep palmar arch.

  • Branches: Arteria radialis indicis and arteria princeps pollicis.

• The Superficial Palmar Arch

  • Direct continuation of the ulnar artery.

  • Curves laterally behind the palmar aponeurosis.

  • Completed by a superficial palmar branch from the radial artery.

  • Position: Distal to the deep arch, approximately at the level of the distal border of the extended thumb.

  • Output: Gives off digital arteries from its convexity to supply the fingers.

• The Deep Palmar Arch

  • Continuation of the radial artery.

  • Curves medially beneath the long flexor tendons, in front of the metacarpal bones and interosseous muscles.

  • Completed on the medial side by the deep branch of the ulnar artery.

  • Position: At the level of the proximal border of the extended thumb.

  • Branches:

    • Superiorly to join the wrist joint anastomosis.

    • Inferiorly to join branches of the superficial palmar arch.

Veins of the Upper Limb

• Classification

  • Superficial Veins: Located immediately beneath the skin in superficial fascia.

  • Deep Veins: Accompany the arteries and are known as venae comitantes (generally in pairs).

• Superficial Vein System

  • Dorsal Venous Arch: Formed by dorsal digital veins draining into dorsal metacarpal veins. Located on the dorsum of the hand proximal to the metacarpophalangeal joints. Drains laterally into the cephalic vein and medially into the basilic vein.

  • Cephalic Vein: Arises from the lateral end of the dorsal venous arch. Ascends on the radial side of the forearm, through the deltopectoral groove, and pierces the clavipectoral fascia to drain into the axillary vein.

  • Basilic Vein: Arises from the medial end of the dorsal venous arch. Ascends on the ulnar side of the forearm. In the mid-arm, it pierces the deep fascia to join the brachial or axillary vein.

  • Median Cubital Vein: Links the cephalic and basilic veins in the cubital fossa. It is a frequent site for venipuncture.

• Deep Vein System

  • Venae comitantes: Arranged in pairs on either side of corresponding arteries, connected by short transverse branches.

  • Includes superficial and deep palmar venous arches.

  • Forearm: Radial and ulnar veins (pairs).

  • Arm: Brachial veins (one on each side of the brachial artery).

  • Axillary Vein: Begins at the lower border of the Teres major as the continuation of the basilic vein. Ends at the outer border of the $1^{st}$ rib as the subclavian vein. Receives brachial veins and the cephalic vein.

  • Subclavian Vein: Extends from the outer border of the $1^{st}$ rib to the sternal end of the clavicle. Unites with the internal jugular vein to form the brachiocephalic (innominate) vein.

Clinical Anatomy and Applications

• Palpation and Pulse Sites

  • Brachial Artery: Palpated in the arm against the brachialis muscle, overlapped laterally by the biceps brachii.

  • Radial Artery:

    • Radial pulse: Superficial to the distal end of the radius between the tendons of brachioradialis and flexor carpi radialis.

    • Anatomical Snuffbox: Palpable as it crosses this region.

  • Ulnar Artery: Palpated as it crosses anterior to the flexor retinaculum, lateral to the pisiform bone.

• Vein Catheterization

  • The cephalic vein is considered difficult for catheterization at its termination because it joins the axillary vein at a right angle and often does not increase in size as it ascends, sometimes dividing into smaller branches.

• Raynaud's Disease

  • A vasospastic disease involving the digital arteries.

  • Causes vascular changes and may lead to necrosis of the fingers.

  • Treatment may require cervicodorsal preganglionic sympathectomy to prevent tissue death.