Major Anatomic Variations of the Upper Extremity Superficial Lymphatic System.

Abstract

Background: Lymphatic anatomy has traditionally been described through cadaveric dissections. Mapping of the upper extremity superficial lymphatic system with indocyanine green (ICG) lymphography provides functional insights and reveals major anatomic variations.

Methods: Healthy women underwent lymphatic mapping of the upper extremities with ICG lymphography. ICG was injected in 6 standard sites in the hand/wrist and upper arm. Major anatomic variations of 4 main forearm pathways and connectivity to 4 upper arm pathways were revealed.

Results: Ninety arms of 45 participants were included. The posterior radial channel predominantly courses in the dorsal forearm (98%). The posterior ulnar forearm pathway courses in the dorsal forearm in the majority of arms (70%). The anterior radial and anterior ulnar forearm channels exclusively course in the volar forearm (100%). The posterior radial pathway connects to the bicipital (80%), lateral (48%), medial (9%), and tricipital (7%) upper am pathways. The posterior ulnar pathway connects to the lateral (54%), tricipital (51%), medial (21%), and bicipital (14%) upper arm pathways. The anterior radial pathway connects to the medial (50%) and bicipital (60%) pathways. The anterior ulnar pathway connects to the medial (54%) and bicipital (59%) pathways.

Conclusions: Upper extremity lymphatic drainage to the lateral and tricipital pathways is enabled exclusively by the dorsal forearm channels, suggesting their importance in breast cancer-related lymphedema risk. Variations of upper extremity lymphatic anatomy are relevant to the risk, prevention, and treatment of breast cancer-related lymphedema risk and warrant further study.