Major Anatomic Variations of the Upper Extremity Superficial Lymphatic System

Lymphatic anatomy has primarily been described in cadaveric dissections. Mapping of the upper extremity superficial lymphatic system with indocyanine green (ICG) lymphography provides functional insights and detail to major anatomic variations.

Healthy female volunteers underwent lymphatic mapping of the upper extremities with ICG lymphography. ICG was injected in six standard sites in the hand/wrist and upper arm. Major anatomic variations of four main forearm pathways and connectivity to four upper arm pathways were described.

90 arms of 45 volunteers 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.

Upper extremity lymphatic drainage to the lateral and tricipital pathways is enabled exclusively by the dorsal forearm channels suggesting their importance in BCRL 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.