Anatomy and imaging of the equine metacarpophalangeal/metatarsophalangeal joint

The metacarpo-/metatarsophalangeal joint is a high motion joint and is therefore prone to be injured. Lameness attributable to the metacarpo-/ metatarsophalangeal joint is a frequent cause of early retirement from athletic activity in horses and should therefore be detected as early as possible. The basis of the examination for lameness remains the clinical examination, including a complete motion examination in which the lameness is unambiguously localized by means of local anesthesia. A combination of radiography and ultrasonography is often sufficient for visualizing the lesions. However, in the absence of clear radiological or ultrasonographical findings, more advanced imaging modalities, such as computed tomography (CT) or magnetic resonance imaging (MRI), are necessary. The choice of technique largely depends on the tissue characteristics of the expected lesion, the cost restraints of the owner, and the willingness to take the risk of general anesthesia.