Metacarpal (Fore) & Metatarsal (Hind) Ultrasound
Evaluation of the metacarpus or metatarsus is indicated in horses whose lameness has been localized to either region through the use of diagnostic nerve blocks or in horses with regional swelling. Structures evaluated include the superficial digital flexor tendon, deep digital flexor tendon, inferior check ligament and suspensory ligament. Normal tendons and ligaments show an evenly white or echogenic appearance on transverse (cross-section) views and a linear fiber pattern on longitudinal views. Injuries typically cause enlargement (as measured by cross-sectional area) and create hypoechoic (dark) areas within the injured structure as shown in the center image.
Ultrasound was used to determine that an inferior check ligament (ICL) injury was the cause of swelling and lameness in this Dutch Warmblood show jumper. The top right image shows severe enlargement of the ICL with a hypoechoic (dark) area and irregular fiber pattern. This can be compared to the normal appearance of the ICL (arrows) shown at bottom right.