Ultrasonography of the foot and pastern

Lameness associated with the foot is common and routinely evaluated using radiography. However, many causes of lameness are associated with soft tissue pathology where there are no or minimal radiographic changes. The third phalanx (P3), distal sesamoid bone (navicular bone) (DSB), navicular bursa (NB), implantation of the deep digital flexor tendon (DDFT), distal sesamoid impar ligament (DSBIL), and other suprasolar structures can be evaluated ultrasonographically transcuneally (through the frog) and transsolarly (through the sole). The pastern is an area that, with a little practice, can be evaluated very satisfactorily using the ultrasound machines and probes available in general practice. The use of ultrasonography to investigate lesions in this region of the distal limb is particularly applicable as many injuries to the soft tissue structures on the palmar aspect of the limb result in non-specific subcutaneous fibrosis which prevents accurate digital palpation of the area.