The structure of a tendon sheath is similar to that of a joint capsule or a bursa. One distinguishes one
- outer stratum fibrosum (layer of connective tissue) and a
- inner stratum synoviale (synovial layer ).
The synovial layer forms a double lamella, the outer sheet of which is connected to the connective tissue layer and the inner sheet to the tendon. The transition point between the wall and tendon leaf is the mesotendineum . This can be receded in sections; the remaining remains are then called Vincula . Between the two lamellae there is a gap which is filled with a small amount of a viscous liquid . This is called synovia because of its similarity to egg white and is a product of the synovial layer.
Pathological changes in the tendon sheaths are referred to in medicine as tendovaginopathies . Overuse of tendons or puncture injuries to the tendon sheath can lead to tendonitis ( tendovaginitis ). A tendon sheath fibroma is benign attachment to or near a tendon or tendon sheath.