A patient with TB of the lumbar spine develops a large psoas abscess. The abscess tracks along the psoas sheath and points at the:

• A Gluteal region via the greater sciatic notch
• B Medial thigh, tracking through the obturator foramen
• C Femoral triangle, below the inguinal ligament lateral to the femoral vessels ✓
• D Perineum via the lesser sciatic foramen

Explanation

A psoas (iliopsoas) abscess from lumbar spinal TB tracks along the psoas sheath (formed by the fascia iliaca). The psoas muscle originates from L1-L5 vertebral bodies and inserts with the iliacus onto the lesser trochanter. The abscess thus follows the muscle beneath the inguinal ligament (under the iliac fascia) and presents in the femoral triangle, lateral to the femoral vessels (since the psoas inserts laterally to the femoral sheath). This creates the characteristic 'pointing' abscess in the upper medial thigh/femoral triangle area.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.