The fourth lumbar vertebra (L4) controls knee and hip movement and is approximately even with the top of the hip bone. Sciatica may occur if this vertebra is damaged.
• Connections: sigmoid, muscles of the lower back, sciatic nerve, large intestine, bladder, prostate gland
• Possible problems: sciatica, lumbago, back aches, prostate trouble, difficult, painful, or too frequent urination
