• sheath
  • When the associated swelling of the sheath severely narrows the space normally required for a tendon to pass freely through its tunnel and beneath the pulleys and ligaments, the condition is known as stenosing tenosynovitis. (arthroscopy.com)
  • Tenosynovitis most commonly results from the introduction of bacteria into a sheath through a puncture or laceration wound, though bacteria can also be spread from adjacent tissue or via hematogenous spread. (wikipedia.org)