Superficial and Functional Imaging of the Posterior Upper Arm Pathway in the Healthy Population

The posterior upper arm (PUA), or tricipital, pathway is a superficial lymphatic channel that has been postulated to be a compensatory pathway for lymphatic drainage of the upper extremity following axillary lymph node dissection (ALND). The PUA pathway has been characterized in the breast cancer population but not in the healthy population.

Healthy female volunteers were recruited for bilateral mapping of the upper extremities using indocyanine green (ICG) lymphography. Phenotypic variants of the PUA pathway were recorded.

57 volunteers underwent ICG lymphography of the bilateral arms. The PUA pathway was visualized in 100% of arms. In 46% of arms, the pathway was continuous with the forearm (long bundle phenotype), whereas in 54% of arms, the pathway had no continuity with the forearm (short bundle phenotype).

The PUA pathway was universally present in healthy volunteers. However, in comparison to our prior study, which was performed in patients with breast cancer prior to ALND, healthy volunteer arms more often displayed the short bundle phenotype. Defining the incidence of PUA pathway anatomic variants in healthy subjects is important to further understand its potential role in the development of lymphedema.