Subinguinal Space

spatium subinguinale

The subinguinal space is the gap beneath the inguinal ligament between the anterior superior iliac spine and the pubic tubercle, through which the iliopsoas, pectineus, femoral nerve, femoral artery, femoral vein, and femoral canal pass from the abdomen into the thigh. The muscular lacuna (lateral) and vascular lacuna (medial) are its two subdivisions.

Region: Thigh

Clinical Relevance

Clinical Notes

The subinguinal space is the site of femoral nerve block, which is the primary regional technique for femoral shaft and knee surgery. The femoral nerve lies lateral to the femoral artery in the muscular lacuna and is blocked with in-plane ultrasound guidance. Femoral nerve compression at this level by haematoma, lipoma, or lymphadenopathy produces femoral neuropathy with anterior thigh numbness and quadriceps weakness.

Pathology

Common Injuries & Conditions

Femoral Neuropathy

Compression of the femoral nerve in the subinguinal space from haematoma, psoas abscess, or lymphadenopathy producing quadriceps weakness, loss of the patellar reflex, and anterior thigh and medial leg numbness.