Parasternal lymph nodes

The parasternal lymph nodes are a group of thoracic lymph nodes located alongside the internal thoracic (internal mammary) vessels, close to the sternum. They play an important role in draining lymph from the anterior thoracic wall, breasts, upper abdominal wall, and parts of the upper peritoneal cavity. These nodes are clinically significant due to their involvement in breast cancer lymphatic spread and thoracic wall infections.

Location

• Situated alongside the internal thoracic arteries and veins
• Located posterior to the upper six costal cartilages and adjacent to the sternum
• Lie within the anterior part of the thoracic cavity, along the edges of the sternum in the parasternal region

Afferent Drainage

The parasternal nodes receive lymph from the following areas:

• Anterior thoracic wall, including skin and muscles
• Medial quadrants of the breast (especially in females)
• Upper anterior abdominal wall (via superficial and deep channels)
• Upper surface of the liver (via lymphatics accompanying the falciform ligament)
• Costal pleura and anterior mediastinum

Efferent Drainage

• Lymph from the parasternal nodes drains into the bronchomediastinal lymph trunks
• Ultimately empties into the right lymphatic duct (right side) or thoracic duct (left side)
• May also connect with deep cervical lymph nodes superiorly

Function

• Filters lymph from the anterior thoracic and upper abdominal walls
• Serves as a pathway for metastatic spread from the breast and anterior mediastinal organs
• Plays a role in draining subdiaphragmatic lymph from the liver region

Relations

• Anterior: Costal cartilages and sternum
• Posterior: Transversus thoracis muscle
• Medial: Sternum
• Lateral: Internal thoracic vessels

Clinical Significance)

• Breast cancer: Parasternal lymph nodes are a key route of metastasis from the medial portions of the breast
• Biopsy relevance: May be sampled for cancer staging or sentinel node identification in breast surgery
• Lymphadenopathy: Enlargement can occur in infections or malignancies involving the anterior thoracic wall or liver
• Radiological visibility: Enlarged parasternal nodes may be visible on CT scans near the sternum

Topographic Summary

• Location: Along internal thoracic vessels, near sternum, behind costal cartilages 1–6
• Afferents: From anterior thoracic wall, breast, upper abdomen, liver (via falciform ligament)
• Efferents: To bronchomediastinal trunks → thoracic/right lymphatic duct
• Function: Filters lymph from anterior body wall and mediastinal structures