What happens under the flexor tendons of the fingers in dactylitis?

Abstract

Aim: Tenosynovitis is one of the most frequently described inflammatory lesions in psoriatic dactylitis. The aim of the study was to assess by ultrasound the distribution of content within the synovial sheath of the finger flexor tendons in a cadaveric experimental model of tenosynovitis and to describe anatomically the elements of the space between the flexor tendons and the palmar aspect of the proximal phalanx of the fingers.Material and method: Silicone was injected under ultrasound guidance into the digital flexor sheath of the index finger of a hand specimen. Ultrasound images of the distribution of the filling of the flexor synovial space with the injected material were obtained. These images were compared with images from patients with psoriatic dactylitis. The palmar regions of the hand and fingers were dissected to check the distribution of the injected silicone in the synovial cavity. Additionally, we dissected the 2nd to 5th fingers of five cadaveric hands, including the one used for the experiment.Results: During the injection of the substance, we observed an increasing homogeneous hypoechoic band around the flexor tendons that differed from the images of patients. Dissection of the specimen showed the injected silicone distributed throughout the digital flexor sheath to the distal interphalangeal joint. In addition, we provided an illustrated anatomical description of the elements located between the flexor tendons and the palmar aspect of the proximal phalanx, the inflammation of which could simulate flexor tenosynovitis.Conclusion: The observations of this study may contribute to a better understanding of the anatomical structures involved in PsA dactylitis.

The vincula system - an anatomical and functional crossroad

“…In this framework, Naredo et al [18] compares and discusses sonopathology elements in a mechanical model of digital tenosynovitis obtained in cadavers (intra-tendon sheath silicon injection) versus inflammatory tenosynovitis in PsA patients. The results of this study reiterate not only the importance of the SEC underpinning the structures involvement in PsA but also highlights for the first time the importance of the vincula system involvement and its contribution to the local inflammatory lesion spectrum, generating particular grey scale and Doppler ultrasound findings.…”

“…Moreover, among the vincula system variety (number and precise location) described in anatomical studies [8,18], apparently there is also a vascular pattern variety showing different kind of anastomoses between the arterial branches at metacarpo-phalangeal joints (MCPj) and the first phalangeal level. Recently, Baksa et al [19] described the vascular supply to the MCP joint showing the presence of two distinct vascular territories: the metacarpal half that receives arteries from the palmar metacarpal arteries or proper palmar digital arteries, while the phalangeal half is supplied by both proper and common 6 M. C. Micu, C. M. García-de-Pereda-Notario…”