(8) The meter measures the difference in voltage between the two sides of the glass and converts this potential difference into a pH reading. (9) Reference electrode acts as a baseline or reference for the measurementâor you can think of it as simply completing the circuit.
The most common causes are: Patellofremoral pain-this is mainly an injury felt at the front of the knee but can also cause symtoms on the inside of the knee. Medial meniscus tear-is a tear or degeneration of the semi cicular cartilage discs found in the knee joint.he most common causes are: Referred pain-which can come from an injury or problem in the lower back, front of the knee or other nerve problem in the hip of buttocks. Biceps femoris tendinopathy-which is inflammation or degeneration of the tendon of one of the hamstring muscles as it inserts into the back of the knee.
Other conditions that cause knee pain include: 1  Bursitis. 2  A bursa is a sac of fluid that resides below the skin overlying your joints. 3  Overuse, a fall, or repeated bending and kneeling can irritate the bursa overlying the knee cap (patella), causing pain and swelling.