The quadriceps tendon is the thick tendon that connects the four muscles of the quadriceps group in the front of the thigh to the top of the patella (kneecap). It plays a critical role in straightening the knee and supporting the leg during walking, running, and jumping. On ultrasound, the normal quadriceps tendon appears as a well-defined, echogenic (bright) fibrillar structure with a characteristic layered pattern. Tears of the quadriceps tendon, which most commonly occur at or near the patellar attachment, appear as areas of tendon discontinuity, hypoechoic defects, or retraction of the tendon fibers. Dynamic ultrasound, performed while the patient extends and flexes the knee, can help assess the extent of a tear and the gap between torn ends. Ultrasound is an excellent first-line imaging tool for evaluating suspected quadriceps tendon injuries.