Clinical: 49 y/o with dorsal pain; no trauma
Dx: Distal Intersection Syndrome (Distal Intersection Tenosynovitis)
The proposed underlying pathogenesis of EPL tendinopathy or rupture is akin to the more publicized intersection syndrome in the distal forearm: in the classic form of intersection syndrome, the tendons of the first extensor compartment (abductor pollicis longus and extensor pollicis brevis) cross over the tendons of the second compartment (ECRB and ECRL) in the distal forearm, resulting in a
mechanically disadvantageous anatomical arrangement, which predisposes to tenosynovitis or peritendinitis. The tendons of the second extensor compartment are crossed over once again 3–5 cm more distally; this time by the EPL tendon as it swings past the distal end of Lister’s tubercle, in what has been called the distal or second intersection . Inflammation of the ECRB and ECRL tendon sheath would
extend to the tendon sheath of the EPL, leading to tenosynovitis and possible eventual rupture . The presence of normal communications between the second and third compartment extensor tendon sheaths on tenography lends anatomical credibility to this pathogenetic hypothesis .
- Parellada A, Gopez A, Morrison W, Sweet S, Leinberry C, Reiter S, Kohn M. Skeletal Radiol: 2007 – vol. 36, pp. 203-208.