Page 146 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.3 The foot 121

VetBooks.ir Differential diagnosis analgesia of the DDFT sheath has low sensitivity and
specificity for tendon lesions inside the hoof capsule.
All other causes of foot lameness without radio-
Foot radiographs are generally normal. The pres-
graphic abnormalities, either acute and severe
(fracture, severe collateral desmitis, solar bruise or ence of dystrophic tendon mineralisation is rare.
abscess) or mild and insidious (navicular disease, Most horses with significant radiographic abnor-
pedal osteitis, DIP joint pain, collateral desmitis). malities of the flexor surface of the navicular bone
will have some erosive damage to the dorsal surface
Diagnosis of the tendon. Access for ultrasound is limited to the
Lameness can be significantly improved in two-thirds palmar aspect of the pastern and the proximal recess
of horses with either a palmar digital nerve block, intra- of the navicular bursa. Ultrasonography therefore
articular analgesia of the DIP joint or analgesia of the underestimates the extent and the true prevalence of
navicular bursa. An abaxial sesamoid nerve block is usu- injury. Tendinitis of the DDFT in the foot is pre-
ally required to abolish lameness completely. Intrathecal dominantly an MRI diagnosis (Figs. 1.209–1.211).

1.209 1.210

1.211

Figs. 1.209–1.211 T1-weighted, fat-suppressed
MR images of different lesion types of the deep digital
flexor tendon in the foot (arrows): 1.209 – core lesion;
1.210 – parasagittal split; 1.211 – insertional tear.