Equine Health Update EHU Vol 21 Issue 02 | Page 41

Lateromedial (LM) • • • • The X-ray beam should be horizontal. For a true lateromedial the beam must be perpendicular to the dorsopalmar axis of the leg at the level of the fetlock joint. Palpating the medial and lateral epicondyles of the third metacarpal bones may aid determination of the correct angle. Centre at the level of the distal condyles of the third metacarpal bone. Collimate to include the distal one third of the metacarpus and at least the proximal one half of the proximal phalanx in the image. For a true lateromedial radiograph (left image), the sagittal ridge of the third metacarpal bone (arrow) should be visible and the condyles should be superimposed (arrowhead), allowing clear visualisation of the joint space. If the radiograph is oblique (right image) then sagittal ridge cannot be evaluated and realignment of the beam relative to the fetlock is necessary to achieve adequate diagnostic quality. • Volume 21 Issue 2 | May 2019 • 41