Involucrum in chronic osteomyelitis is best described as:
- A New bone formed by stripped periosteum encasing the sequestrum ✓
- B Dead bone separated from living bone
- C A sinus tract connecting bone to skin surface
- D An abscess cavity within the bone (Brodie's abscess)
Correct answer: A. New bone formed by stripped periosteum encasing the sequestrum
Explanation
In chronic osteomyelitis, the elevated periosteum forms new bone around the dead sequestrum — this envelope is the involucrum. The involucrum has openings called 'cloacae' through which pus tracks to the skin surface via sinuses. The sequestrum (dead avascular bone) lies within the involucrum. Treatment involves sequestrectomy and saucerisation — removing the sequestrum through the cloaca. Without treatment, the sequestrum perpetuates infection as it acts as a foreign body that antibiotics cannot penetrate.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.