The Right Lymphatic Duct (RLD) is one of the two main terminal vessels in the human lymphatic system. This duct collects lymph, which contains proteins, immune cells, and waste products, from a specific portion of the body. Its purpose is to return this filtered fluid back into the bloodstream for circulation at a major vein near the neck.
The Precise Anatomical Course
The Right Lymphatic Duct has a short course, typically measuring only one to two centimeters in length in an adult. Its location is confined to the root of the neck, sitting near the right collarbone. The duct is formed by the convergence of three major collecting vessels, known as trunks, which gather lymph from the upper right quadrant of the body.
These tributaries include the right jugular trunk, which drains the right side of the head and neck, and the right subclavian trunk, which drains the right upper limb. The third major vessel is the right bronchomediastinal trunk, which collects lymph from the right side of the chest cavity. The duct’s final path takes it along the medial border of the anterior scalene muscle, located deep in the neck.
The RLD empties its collected lymph into the venous circulation at the right venous angle. This angle is the junction where the right internal jugular vein and the right subclavian vein meet. This connection allows the filtered lymph to rejoin the blood supply just before it enters the superior vena cava.
While confluence into the venous angle is the most common termination, the precise anatomy of the RLD can vary significantly among individuals. In some cases, the RLD may not form as a single duct at all. Instead, the three lymphatic trunks—jugular, subclavian, and bronchomediastinal—may open independently into the nearby veins or the venous angle.
Defining the Drainage Territory
The territory served by the Right Lymphatic Duct is the upper right quarter of the body. Lymph flowing into this duct originates from the right side of the head and neck.
The entire right upper limb, including the shoulder, arm, forearm, and hand, is drained through the right subclavian trunk. The right side of the thorax, or chest cavity, also contributes its lymph to the RLD via the bronchomediastinal trunk.
This drainage includes the right lung, the right side of the heart, and the convex surface of the liver. The system is compartmentalized, with a clear boundary running down the midline of the body. Understanding the RLD’s defined territory is important for localized fluid balance and the potential spread of disease.
Context within the Major Lymphatic System
The Right Lymphatic Duct operates as part of a dual drainage system alongside the Thoracic Duct. The RLD collects about one-quarter of the body’s total lymph volume. In contrast, the Thoracic Duct handles the remaining 75% of the body’s lymph, making it the main lymphatic vessel.
The Thoracic Duct drains the entire lower body, including both legs and the abdomen. It also handles the left side of the thorax, the left upper limb, and the entire left side of the head and neck. This asymmetrical arrangement ensures the majority of the body’s fluid is processed through the larger duct before returning to the circulation.
The RLD is important for preventing localized swelling, or edema, in its drainage territory. Damage or blockage to the RLD can result in lymphedema, characterized by fluid accumulation and swelling localized to the right upper limb, head, or chest.