SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Swelling in the region of the DDFT in the pastern is usually associated with
enlargement of the deep digital flexor tendon, focal or diffuse areas of decreased
echogenicity, and/or poor definitions of the margins of the tendons.
Lateral DDF tendinitis and digital sheath tenosynovitis
Calcification is frequently found in the DDFT in the region of the fetlock annular
ligament. Disruption of the DDFT in the pastern region is often associated with
disruption in the distal metacarpal or distal metatarsal portion of the tendon. Lesions
usually extend at least 4 - 6 cm or more in a proximal to distal direction, with areas of
calcification in the deep digital flexor tendon extending 6 - 8 cm in length. DDFT injuries
also occur associated with navicular disease or injury to the DDFT in the distal pastern
and foot. In some horses the lameness is intermittent initially, with no local swelling and
clinical signs similar to navicular disease. The DDFT tendinitis that occurs in the distal
pastern region in the area of the navicular bone is difficult to image sonographically.
Distal sesamoidean ligament desmitis
Middle (oblique) distal sesamoidean ligament desmitis: Desmitis of the MDSL is most
common and has been seen in all types of performance horses. Swelling in the pastern
region in horses with MDSL is fairly characteristic because this ligament runs
diagonally across the proximal to mid pastern and swelling of the pastern usually
occurs in this direction. Most horses have local swelling, heat, pain and sensitivity in the
affected ligament and lameness in the affected leg. Subluxation of the PIP joint can
occur in horses with complete rupture of the MDSL. Distal sesamoidean ligament
injuries involving the medial branch of the MDSL is more common than the lateral
branch and hind limb injuries to the MDSL are rare. Suspensory ligament desmitis may
be present in the same limb in affected horses. Prognosis for horses with MDSL is
guarded for returning successfully to performance and the incidence of recurrence is
high if the lesion is large.
The MDSL originates at the base of the sesamoid bones as two large round discrete
branches, which become somewhat oval in appearance. The MDSL branches merge
dorsal to the DDFT in the mid pastern region into a broad rectangular band which
inserts on the palmar or plantar aspect of the distal portion of the first phalanx. The
MDSL branches appear less echogenic because of their oblique orientation and it is
difficult to properly align the transducer and eliminate the off normal incidence artifact.
The branches are thicker in the medial to lateral direction proximally than just prior to
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