Major Anatomic Variations of the Upper Extremity Superficial Lymphatic System

Area of Science:

• Anatomy
• Physiology
• Medical Imaging

Background:

• Traditional lymphatic anatomy relies on cadaveric dissections.
• Indocyanine green (ICG) lymphography offers functional insights into the superficial lymphatic system.
• ICG lymphography details major anatomic variations in the upper extremity.

Purpose of the Study:

• To map the functional anatomy of the upper extremity superficial lymphatic system.
• To identify major anatomic variations and pathway connectivity using ICG lymphography.
• To correlate lymphatic drainage patterns with breast cancer-related lymphedema (BCRL) risk.

Main Methods:

• Healthy female volunteers underwent ICG lymphography of the upper extremities.
• ICG was injected at standard sites in the hand/wrist and upper arm.
• Four main forearm pathways and their connectivity to four upper arm pathways were analyzed.

Main Results:

• 90 arms from 45 volunteers were analyzed.
• Posterior radial and ulnar forearm pathways predominantly course dorsally.
• Anterior radial and ulnar forearm pathways exclusively course volarly.
• Specific forearm pathways showed distinct connections to upper arm lymphatic channels.

Conclusions:

• Dorsal forearm lymphatic channels exclusively drain to lateral and tricipital upper arm pathways.
• These dorsal forearm pathways are crucial for understanding BCRL risk.
• Anatomic variations in upper extremity lymphatics are significant for BCRL prevention and treatment.