The diagnosis of a stifle disorder can be a challenge and various imaging modalities are routinely used
to arrive at an accurate diagnosis. This study describes the normal ultrasonographic anatomy in
relation to cross sectional anatomy. Patellar and collateral ligaments: lig. popliteum obliquum and
common tendon of origin of the Mm. extensor digitorum longus and peroneus tertius were imaged in
longitudinal planes as homogeneous, echogenic structures with linear pattern. In the transverse planes,
they are difficult to differentiate from the surrounding because small diameter and linear fibers not
appear but can be evaluated in tendon because of the tendon synovial sheath. The bone surfaces of the
patella, femur and tibia were imaged as hyperechoic structures. The infrapatellar fat pad appears as
heterogeneous echogenic structure with hyperechoic dots. The joint capsule could not be
differentiated from the adjoining soft tissues, as they showed the same echogenicity.