“Three Stories” is the House M.D. episode that reveals the cause of House’s leg injury.
The episode, written by David Shore, uses a lecture structure in which House presents three diagnostic cases to medical students. One case gradually becomes a disguised account of House’s own medical crisis, allowing the audience to learn why he walks with a cane and experiences persistent pain.
House suffered an infarction in the quadriceps muscle of his right leg. The damage was initially misdiagnosed, and the eventual treatment left him with permanent impairment. This history explains both his limp and his reliance on pain medication.
“Three Stories” is the 21st episode of season 1 and first aired in 2005. Its unusual narrative structure and award-winning script made it one of the show’s most acclaimed early episodes.