Lower Back Pain

Lower back pain - knee pain - knee extension

Patients with lower back pain will often complain of knee pain. The most common roots to be irritated are the L5 and S1 nerve roots which supply many muscles that cross the knee or insert near the knee. Therefore when muscles such as the hamstrings, gluteus maximus, adductor magnus and tensor fascia latae shorten due to spasm, knee pain can often be felt.

Knee pain will be more noticeable on extension (straightening) of the knee or with excessive bending or weight bearing on the knees such as in crawling or kneeling. If the muscles that bend the knee such as the hamstrings go into spasm, knee pain will be felt with knee extension. When the knee extensors such as the tensor fascia latae and the gluteus maximus (through its insertion into the iliotibial tract) shorten due to spasm, knee pain will be felt with knee flexion (bending).

Chief extensors of the knee are the quadriceps (vastus lateralis, vastus medialis, vastus intermedius and rectus femoris) muscles supplied by the femoral nerve (L2, L3, L4).

It is very important that treatments related to problems with knee extension should not be focussed only to treating the quadriceps muscles.

Nerve related muscle pain assessment causing knee pain should include assessment of the movements of the entire spine from the neck to the lower back, hips, knees and ankles.

Lower back pain - hip extension

Lower back pain caused by S1 nerve root irritation will affect the hip extensor muscles which S1 nerve root so richly supplies. The hip extensor muscles are best tested by having the patient lie facedown. The patient bends the knee and lifts the knee off the surface of the bed. The examiner can test the strength of the gluteus maximus muscle by pushing down on the buttock and thigh toward the bed while the patient resists the hip from moving down. If the patient lifts the hip and thigh off the surface of the bed with the knee straight, this movement is primarily performed by the hamstring muscles. The muscles which perform hip extension are: - gluteus maximus (inferior gluteal nerve carrying L5, S1 root fibers primarily S1) - biceps femoris, long head (sciatic nerve carrying L5, S1 root fibers primarily S1) - semitendinosus (sciatic nerve carrying L5, S1 root fibers primarily L5) - semimembranosus (sciatic nerve carrying L5, S1 root fibers primarily L5) © 2007 copyright all rights reserved http://www.stopmusclepain.com Lower back pain/hip extension