Depth of the Deepest Inguinal Lymph Node
The deepest inguinal lymph nodes are located deep to the cribriform fascia, within the femoral triangle, and can be found at a depth of approximately 1 cm from the skin surface. 1
Anatomical Location of Inguinal Lymph Nodes
Inguinal lymph nodes are classified into two main groups:
- Superficial inguinal lymph nodes: Located in the subcutaneous tissue above the fascia lata 1
- Deep inguinal lymph nodes: Located deep to the cribriform fascia, within the proximal femoral triangle 1
The inguinofemoral lymphadenectomy procedure, which is often performed in vulvar cancer treatment, involves removal of both superficial and deep lymph nodes:
- The superficial nodes are located superficial to the inguinal ligament 1
- The deep femoral nodes are found within the proximal femoral triangle 1
- The deepest nodes are positioned deep to the cribriform fascia 1
Distribution of Inguinal Lymph Nodes
The distribution of inguinal lymph nodes varies by location:
- Superficial nodes are more numerous (mean of 13.60 nodes) compared to deep nodes (mean of 1.71 nodes) 2
- The highest concentration of superficial nodes is found in the superomedial quarter of the inguinal region 2
- The lowest concentration is in the inferolateral quarter 2
Surgical Relevance
Understanding the depth and distribution of inguinal lymph nodes is crucial for:
- Complete oncological resection: Inguinofemoral lymphadenectomy must include nodes deep to the cribriform fascia to ensure adequate removal of potential metastatic disease 1
- Radiation planning: When contouring inguinal nodes for radiation therapy, margins of at least 2 cm around femoral vessels are required in most directions to adequately cover the nodal region 3
Clinical Implications
The depth of inguinal lymph nodes has important implications for:
- Surgical approach: The standard surgical approach involves resection to the deep fascia or a minimum of 1 cm tissue depth 1
- Lymphatic drainage: The deep femoral nodes typically lie medial to the portion of the femoral vein located within the fossa ovalis 4
- Sentinel lymph node biopsy: When performing sentinel node procedures, understanding the depth is crucial to avoid missing deeper nodes 1
Anatomical Boundaries
The anatomical boundaries of the deep inguinal nodes are:
- Laterally: Medial border of the iliopsoas muscle 3
- Medially: Lateral border of adductor longus or medial end of pectineus 3
- Posteriorly: Iliopsoas muscle laterally and anterior aspect of the pectineus muscle 3
- Anteriorly: The anterior edge of the sartorius muscle 3
Understanding these boundaries is essential for complete surgical dissection and accurate radiation therapy planning to ensure optimal oncological outcomes while minimizing morbidity.