Arterial Supply and Venous Drainage

Arterial Supply and Venous Drainage

Arterial Supply and Venous Drainage

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Axillary Artery - Armpit's Pipeline

  • Course: Continuation of subclavian artery; lateral border of 1st rib to inferior border of teres major, becomes brachial artery.
  • Key Relation: Pectoralis minor muscle divides it into three parts.
    • 1st Part (medial to muscle): 1 branch.
      • Superior Thoracic Artery.
    • 2nd Part (posterior to muscle): 2 branches.
      • Thoracoacromial Artery (Branches: Acromial, Clavicular, Pectoral, Deltoid - 📌 CADP).
      • Lateral Thoracic Artery (supplies serratus anterior).
    • 3rd Part (lateral to muscle): 3 branches.
      • Subscapular Artery (largest; gives Circumflex Scapular & Thoracodorsal A.).
      • Anterior Circumflex Humeral Artery.
      • Posterior Circumflex Humeral Artery.

Axillary artery and branches schematic

⭐ > Posterior circumflex humeral artery & axillary nerve pass quadrangular space. Vulnerable: surgical neck humerus fracture (deltoid/teres minor paralysis, sensory loss).

Brachial Artery - Bicep's Bloodline

  • Origin: Continuation of axillary artery from teres major's lower border.
  • Course: Descends in anterior arm compartment, medial to biceps brachii.
  • Termination: Bifurcates into radial & ulnar arteries at cubital fossa (level of radius neck).
  • Key Relations:
    • Median nerve: Initially lateral, crosses anteriorly (mid-arm), then medial distally (📌 L-A-M: Lateral-Anterior-Medial).
  • Main Branches:
    • Profunda brachii artery (accompanies radial nerve in spiral groove).
    • Superior ulnar collateral artery.
    • Inferior ulnar collateral artery.
    • Muscular branches.
  • Clinical Points:
    • Brachial pulse: Palpated medial to biceps tendon in cubital fossa.
    • Site for blood pressure measurement. Brachial Artery and Median Nerve Anatomy

⭐ Injury to the brachial artery, e.g., in supracondylar fracture of humerus, can lead to Volkmann's ischemic contracture.

Forearm & Hand Arteries - Pulse & Palm Providers

  • Radial Artery:
    • Lateral forearm; pulse at wrist (lateral to Flexor Carpi Radialis tendon).
    • Branches: Princeps pollicis, Radialis indicis.
    • Mainly forms Deep Palmar Arch (DPA).
  • Ulnar Artery:
    • Medial forearm; travels with ulnar nerve (superficial to flexor retinaculum).
    • Branch: Common Interosseous Artery (CIA) → Anterior & Posterior Interosseous Arteries.
    • Mainly forms Superficial Palmar Arch (SPA).
  • Palmar Arches:
    • SPA: Ulnar A. (major contribution) + Radial A. (superficial palmar branch). More distal.
    • DPA: Radial A. (major contribution) + Ulnar A. (deep palmar branch). More proximal.
    • Supply digits via common and proper palmar digital arteries.
  • 📌 Allen's Test: Assesses patency of radial & ulnar arteries and integrity of palmar arches before radial artery cannulation or ABG sampling.

⭐ The superficial palmar arch is completed by the superficial palmar branch of the radial artery in ~30-40% of individuals; it can also be formed solely by the ulnar artery or by a median artery variant.

Arterial supply of hand showing palmar arches

Upper Limb Veins - Blue Return Routes

  • Superficial Veins: Located in subcutaneous tissue; primary drainage route from skin and superficial fascia.
    • Cephalic Vein:
      • Origin: Lateral side of dorsal venous arch of hand.
      • Course: Ascends anterolaterally; passes in deltopectoral groove.
      • Termination: Drains into axillary vein after piercing clavipectoral fascia.
    • Basilic Vein:
      • Origin: Medial side of dorsal venous arch.
      • Course: Ascends posteromedially; pierces deep fascia mid-arm.
      • Termination: Joins brachial veins to form axillary vein.
    • Median Cubital Vein:
      • Connects cephalic and basilic veins in cubital fossa.
      • 📌 Preferred site for venipuncture.
  • Deep Veins: Accompany arteries (venae comitantes); e.g., radial, ulnar, brachial veins.
    • Axillary Vein:
      • Formation: Union of basilic vein and brachial veins (venae comitantes of brachial artery).
      • Continuation: Becomes subclavian vein at the outer border of the 1st rib.
  • Perforating Veins: Connect superficial and deep venous systems, ensuring unidirectional flow.

Upper Limb Veins: Superficial and Deep

⭐ The median cubital vein is the most common site for intravenous injections and blood sampling due to its superficial location and minimal surrounding nerve structures in the cubital fossa, making it easily accessible and relatively safe for the procedure.

High‑Yield Points - ⚡ Biggest Takeaways

  • Axillary artery, from subclavian, has three parts relative to pectoralis minor.
  • Brachial artery continues axillary, bifurcating into radial & ulnar arteries in cubital fossa.
  • Profunda brachii, largest brachial branch, runs with radial nerve in spiral groove.
  • Major superficial veins: cephalic (lateral) and basilic (medial).
  • Median cubital vein links cephalic and basilic in cubital fossa; common for venipuncture.
  • Allen's test confirms palmar arch patency via radial and ulnar arteries.

Practice Questions: Arterial Supply and Venous Drainage

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The vein of Galen is formed by which structure?

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Flashcards: Arterial Supply and Venous Drainage

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The _____ nerve and posterior humeral circumflex artery pass through the quadrangular space of the shoulder.

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The _____ nerve and posterior humeral circumflex artery pass through the quadrangular space of the shoulder.

axillary

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