A 30-year-old man with Pott's spine at T9-T10 has a 'cold abscess'. MRI shows a large prevertebral collection extending to the psoas sheath and tracking down to the groin. Which of the following correctly describes the anatomical pathway of this cold abscess spread?

• A Thoracic prevertebral abscess tracks posterior to the anterior longitudinal ligament, then along the iliopsoas sheath to the femoral triangle ✓
• B Thoracic prevertebral abscess pierces the posterior longitudinal ligament to enter the spinal canal causing cord compression only
• C Abscess tracks through the transverse foramen of adjacent vertebrae to the retroperitoneum
• D Thoracic abscess erodes through the costovertebral joint and tracks along the rib to present as an intercostal abscess

Explanation

Pott's spine cold abscesses from thoracic vertebrae lie anterior to the anterior longitudinal ligament (prevertebral) and track within the fascial plane posterior to the iliopsoas muscle along the psoas sheath, pointing in the femoral triangle (lateral to the femoral artery) or the groin. This is the classic 'psoas abscess' tracking path. Posterior longitudinal ligament penetration causes cord/root compression (extradural abscess), not distant soft-tissue tracking. The transverse foramen route is not the abscess pathway; costovertebral extension causes intercostal tracking but is separate from the psoas path.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.