Which lymphatics coalesce to form the paracaval and para-aortic chains?

The paracaval and para-aortic lymphatic chains are primarily formed by the lymphatics that accompany the common iliac arteries. These chains are critical in the lymphatic drainage of the pelvic region and the lower abdomen, as they collect lymph from various structures within the pelvis and the lower limbs before transporting it to the thoracic duct or directly to the cisterna chyli. This drainage pathway is essential for maintaining fluid balance and immune function in these areas.

The common iliac lymphatics receive lymph fluid from the lower limbs via the femoral lymphatics, but they are the primary contributors to the formation of the paracaval and para-aortic lymphatic chains. In contrast, the lymphatics associated with other arteries like the celiac trunk or subclavian artery drain different regions of the body that do not directly contribute to these specific lymphatic chains. Understanding the anatomy and connections of lymphatics helps in clinical practice, especially in conditions like lymphedema and malignancies that may spread through lymphatic channels.