@visual.healthlab: L4-L5 and L5-S1: 4 Things That Could Be Affecting Your Lower Back L4-L5 and L5-S1 are two important levels of your lumbar spine. Prolonged sitting, repeated bending, poor lifting techniques, and severe nerve compression can contribute to lower back problems. Learn four things to watch out for and recognize the warning signs of foot drop. #L4L5 #L5S1 #LowerBackPain #HerniatedDisc #SpineHealth