Fenestration of tenosynovial capillaries

A proportion of superficial capillaries in joint synovium are known to be fenestrated. The specialized functions of these fenestrated capillaries are unknown. We report the finding of fenestrae in tenosynovial capillaries from rabbit peroneal tendon sheaths. Fenestrations occupied 0.66% of the endothelial surface. Fenestrated capillaries appear to be a general feature of synovium, rather than a specific feature of joint tissue.