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.