The muscle above the knee, usually refers to the lower quadriceps muscle, the muscle swelling in this area may be caused by the following: 1, it may be caused by trauma, such as local impact injuries or local muscle strains during strenuous exercise; 2, it may be a chronic inflammation of the local muscle, most often due to heavy work or strenuous exercise of the lower limbs. The most common is frequent heavy physical labor or strenuous exercise of the lower extremities, resulting in chronic strain pain, swelling, and sterile inflammation of the local muscles; 3, it may be bursitis above the knee, usually seen in acute knee osteoarthritis, usually this condition is usually positive floating patella test, and pressure on the local will feel a sense of fluctuation.