Major Blood Vessels Overview

Overview of Major Blood Vessels

• Discussion of arteries and veins in the upper limb, lower limb, and trunk.

• Focus on testable arterial and venous branches.

Major Arteries in the Upper Limb

• Aorta: Main artery exiting the heart.

  • Brachiocephalic Artery: First major branch from the aorta.

  • Divides into:

    • Right Common Carotid Artery (supplies right side of head/neck)

    • Right Subclavian Artery (supplies right upper limb)

• Left Subclavian Artery: Directly branches off the aortic arch.

  • Both subclavian arteries become Axillary Arteries as they pass through the axilla (armpit).

  • Brachial Artery: Continuation of the axillary artery into the arm.

  • Deep Brachial Artery (Profunda Brachii): Supplies the posterior compartment.

  • Radial Artery: Runs parallel to the radius.

  • Ulnar Artery: Runs alongside the ulna.

• Palmar Arches: Formed by branches of radial and ulnar arteries in the hand, supplying blood to the hand region.

  • Four arches in total, with the largest being the Palmar Arch.

Venous Drainage in the Upper Limb

• Begins from Palmar Venous Arches draining venous blood from the hand.

• Basilic Vein: Superficial vein ascending on the medial side.

• Cephalic Vein: Superficial vein on the lateral side.

• Both veins communicate via the Median Cubital Vein in front of the elbow.

• Deep veins accompany the arteries, sharing names with corresponding arteries (e.g., Ulnar Veins accompany Ulnar Artery).

• Axillary Vein: Formed by the merging of basilic and brachial veins, continues as Subclavian Vein, which joins Internal Jugular Vein to form Brachiocephalic Vein.

Major Arteries in the Trunk

• Descending Aorta: Divided into:

  • Thoracic Aorta (above diaphragm)

    • Parietal Branches: Supply the wall of the thorax (e.g., posterior intercostal arteries).

    • Visceral Branches: Supply organs (e.g., esophageal branches).

  • Abdominal Aorta (below diaphragm)

  • Key Visceral Branches:

    • Celiac Trunk/Artery: Supplies the stomach, pancreas, spleen, and liver.

      • Common Hepatic Artery: Supplies the liver, gallbladder, and parts of the stomach and duodenum.

      • Left Gastric Artery: Supplies the stomach, specifically the lesser curvature, and the lower esophagus.

      • Splenic Artery: Supplies blood to the spleen, pancreas, and portions of the stomach.

    • Superior Mesenteric Artery: Supplies the small intestine and proximal half of the large intestine.

    • Inferior Mesenteric Artery: Supplies the distal half of the large intestine.

Lower Limb Arterial Supply

• Common Iliac Arteries: Branch from the abdominal aorta at L4.

  • Divide into Internal Iliac Artery (supplies pelvic viscera) and External Iliac Artery (supplies lower limb).

• Femoral Artery: Continuation of the external iliac after passing under the inguinal ligament.

  • Branches include Deep Femoral Artery for the posterior compartment.

• Popliteal Artery: Continuation behind the knee, bifurcates into Anterior Tibial Artery and Posterior Tibial Artery:

  • Anterior Tibial: Moves to the anterior compartment.

  • Posterior Tibial: Supplies the posterior and lateral compartments, gives rise to the fibular artery.

• Dorsalis Pedis Artery

  • Continuation of the anterior tibial artery into the foot

Venous Drainage in the Lower Limb

• Superior Vena Cava

  • Drains blood from the upper body to the heart

• Inferior Vena Cava

  • Drains blood from the lower body to the heart

• Azygos Vein

  • Drains the thoracic wall and parts of the upper abdomen

• Common Iliac Vein

  • Formed by the internal and external iliac veins

• Internal Iliac Vein

  • Drains pelvic organs

• External Iliac Vein

  • Drains blood from the lower extremities

• Dorsal Venous Arch: Initiates superficial veins.

• Greater Saphenous Vein: Medial; drains into the femoral vein.

• Small Saphenous Vein: Lateral; drains into the popliteal vein.

Portal Venous System

• Hepatic Portal Vein: Formed by merging:

  • Splenic Vein drains the spleen, Inferior Mesenteric Vein drains the distal colon, Superior Mesenteric Vein drains parts of the intestinal tract.

• Collects venous blood from the digestive tract (except esophagus and oral cavity), routing it through the liver for nutrient metabolism.

• Elevated portal pressure can lead to connections with the caval system, causing esophageal varicosis and hemorrhoids.

Clinical Points

• Varicosis: Occurs when deep veins cannot effectively pump blood, leading to pooling in superficial veins.

• Importance of Muscle Pump: Ensures venous blood is returned to the heart, especially from lower limbs.

• Variations in blood color can indicate the origin of gastrointestinal bleeding (esophageal varicosis vs. ulcerative colitis).