Sciatica is a general term given to pain down the leg. Sciatica may be caused by irritation of the main nerve into the leg by a spinal disc.
Do you think you may have sciatica? But are not really sure. Sciatica in general starts as a back ache. The ache can be central or local to one side or another. The pain may of of gone on for a long time. Often aggravated by lots of smaller less painful back pain episodes with out radiations into the lower extremity or foot. This on going trauma tends to cause small cracks and fissures within the disc structure. This may cause the spinal disc to crack and leak or the disc may bulge and push onto your sciatic nerveas it emerges from your spine. The most common discs that bulge are lumbar four, five and the lumbar sacral disc.
What you want to know is what is it, what caused it but most of all how do you get rid of it!
What is Sciatica? Route of the sciatic nerve down the thigh
Technically speaking, sciatica is a symptom of nerve irritation and not a clear diagnosis. It is a “non-specific” medical term commonly used to describe symptoms of pain, numbness and/or pins and needles radiating downward from the spine, buttock over the posterior or lateral side of the lower limb often into the lower leg or foot. In general it is usually assumed to be caused by compression of a Sciatic nerve by a bulging spinal disc but this is not necessarily so.
A common neurological cause of this pain is entrapment of the sciatic and/or posterior femoral cutaneous nerves. Pain may also be caused by trauma, disc or spine wear (degeneration / spondylosis) spinal stenosis, local nerve neuropathy (many reasons) nerve tension by trigger points in the soft tissue. This latter case is easily overlooked and requires manual palpation of the musculature associated with the hip.
It is often assumed that there is sciatic nerve root entrapment, resulting in the compression of the nerve. Pain and symptoms being transmitted or referred from the low back to one of the buttocks and down the back of the leg along the pathway of the sciatic nerve. Hence the term sciatica.
The exact cause of sciatica is not fully understood but is commonly thought to involve a slipped or herniated disk. This means one of the disks, which lie between each of the vertebra in the lower back (lumbar area), has cracked and allowed some of the inner disk material to protrude out, putting pressure on the adjacent nerve root, which in this case is the sciatic nerve. The term ‘lumbago’ is often banded about as well which is a general term for low back pain. However, some people have been found to have a slipped disk but have no pain.
Symptoms can vary from extreme pain in the low back radiating into one buttock and down the leg. Pain often increases on exertion or bending forward. Alternatively, there may only be a mild sensation in the leg or buttock. There may be numbness in the area, weakness in the leg and diminution of the reflexes. Pain may be triggered by coughing or straining and can be so severe that the lower back becomes locked in sideways bending position (scoliosis) caused by a strong contraction.
Alternatively, it may only come on when sitting or standing in a certain position. Clinical experience indicates that these certain positions are usually associated with continually holding a poor posture either at home or at work. For example, protruding the head forward peering at a computer all day or regularly lifting a baby out of the back of the car. But some or all of these symptoms are also associated with other conditions which is probably why the name is often misused as a catchall word for any pain affecting the buttocks or other parts of the leg. In this case the pain is triggered by a local trapping (trigger point) or straining of the nerve along its pathway. All of which can lead to sciatic-like symptoms, giving rise to conditions such as Piriformis, Psoas, Hamstring Syndromes, Back Pocket Sciatica and Pseudo-Sciatica.
An area of extreme irritability that when compressed is very tender and can give rise to referred pain and tenderness.
As the sciatic nerve passes through the buttock it goes through or under a muscle called the ‘Piriformis’. This muscle lies deep to the large buttock muscles (Gluteus maximus and medius) and is classified as a lateral (outward) rotator of the hip when it is in a neutral weight-bearing position as in standing or when extended during walking or running. In addition, it abducts (away from the center) the thigh when flexed. It also plays a restraining role by controlling medial rotation (inward) during the initial stance phase of walking or running. Sustained tension in this muscle can lead to the formation of trigger points resulting in the compression of the sciatic nerve and possibly the dysfunction of the SI joint (joint between the spine and the pelvis).
This tension in the Piriformis results in symptoms that are easily confused with those of a herniated disc. Absence or marked weakness of the Achilles tendon reflex would suggest a disc lesion. Radiograph reports of the narrowing of the disc space or degenerative changes with spur formation are not by themselves sufficient to account for the pain characteristics of the piriformis syndrome. Degenerative changes occur in the spine with aging and do not correlate well with these symptoms. Recognition of piriformis symptoms may avoid needless laminectomy.
Piriformis Syndrome Symptoms
May be a mixture of seemingly unrelated symptoms. Pain and paresthsias (pins and needles) may be apparent in one or more of these areas: the low back, groin, perineum, buttock, hip, back of the thigh, leg and foot or the SI joint. Swelling can occur in the painful leg and sexual dysfunction can occur. The condition can be aggravated by sitting, getting up, or standing. Conversely, activity can worsen the symptoms. It can also cause the buttock muscles to atrophy. Numbness of the foot and loss of position sense (proprioception) can lead to an unstable walk.
Piriformis syndrome can be activated in numerous seemingly different ways. For example, long drives in the car result in the accelerator foot being flexed for long periods, resulting in the tightening of the piriformis muscle. Lifting or lowering of a heavy weight, catching oneself from falling, twisting sideways while bending or lifting a weight such as a baby out of the back of the car. Direct trauma such as hitting the muscle itself or impact caused by a car accident particularly when the impact is from the side. Morton’s foot (second toe is longer than the big toe) can initiate the syndrome after a long walk. This is because the condition tends to cause medial rotation and adduction (inward movement) of the thigh, which puts a strain on the piriformis.
Gluteus Medius & Iliopsoas muscle tension
No other muscle has so many different functions, cause so much pain and is so difficult to palpate (touch).
Actually two different muscles, the psoas major runs along each side of the lumbar spine to the hip and the iliacus runs from each side of the pelvis joining the psoas at the hip. Their main function is to flex the thigh. The psoas can assist in lumbar extension (lordosis) and is involved in spinal stability. Its involvement in thigh flexion is currently being reconsidered. During running the iliacus is active in thigh flexion and with the psoas during the last 60 of a sit-up.
Trigger points refer pain into the low back, either alongside the spine or across the back. Pain is worse on standing upright and remains as a nagging pain when lying down. Often there is difficulty in getting up at all. Sciatic-like symptoms can be apparent. Pain is often felt in the front of the thigh.
Prolonged sitting, particular in the sloped seats of a car or lorry, causes the continual shortening of these muscles resulting in activation of trigger points in them. Similarly, sleeping with the hips flexed (fetal position) will have the same effect. Trunk rotation and side bending particularly when ‘core stability’ muscles are weak will result in activation of trigger points. Tightness in the anterior thigh muscles (rectus femoris) prevents hip extension, so generating tension in these muscles. Leg length discrepancies can also result in their activation.
The hamstrings which run from the crease of the buttock to the back of the knee are supplied by branches of the sciatic nerve. These muscles extend the thigh at the hip joint and flex the leg at the knee joint. During standing and walking they work indirectly to maintain an erect posture.
Trigger points in the hamstring muscles result in pain being experienced on walking, possibly resulting in a limp. Sitting can also cause pain in the buttock, upper thigh and back of the knee. Pain also occurs on rising from a chair, particularly if sitting crossed legged, and can cause disturbed sleep. Confusingly, pain can be felt in the front of the thigh even though the trouble originates in the back of the thigh.
Because the pain distribution often follows the path of the sciatic nerve, patients are often misdiagnosed as having sciatica.
Classically this is caused by constant pressure on the hamstrings. For example sitting in chairs which have too high a seat. Patio or seaside furniture commonly has a canvas or plastic seat attached to a horizontal bar across the front of the seat. The seat bottom sags and the cross bar presses firmly against the hamstrings. Children placed in high chairs without a foot-rest experience the same problem. Particularly problematic for people with short legs sitting in long legged seating so their feet do not touch the floor.
Pseudo-Sciatica – Gluteus minimus
The smallest and deepest of the gluteal muscles, lying beneath the gluteal medius, its fibres run from the pelvis to the hip. Like the overlying gluteus medius it has a split role in life; the anterior fibres medially rotate the thigh whilst the posterior fibres assist lateral rotation, all fibres contribute to abduction of the thigh. It also helps to stabilise the pelvis during ambulation.
Hip pain that may cause a limp during walking. Lying on the affected side may be too painful and result in disturbed sleep. Pain on rising from sitting and standing up straight. The pain in the hip area can be severe and constant with no let up either lying down or walking. As this muscle lies close to the Piriformis, the pain patterns are similar. Like the Piriformis it can cause SI joint dysfunction. But whereas the Piriformis pain pattern can extend down to the knee, the minimus pattern includes the calf and the thigh. Low back pain in the sacral and sacroiliac regions is most likely be due to problems in the gluteus medius. Pain referred from trigger points in the gluteus medius is less likely to involve the thigh; gluteus maximus trigger points restricts flexion at the hip whilst Piriformis trigger points restricts medial rotation.
Trigger points may be activated by too much, too soon. For example, walking too far or too fast, especially over rough ground; overuse in running and sports such as tennis. Even painful blisters can alter the gait pattern sufficiently, or simply running awkwardly due to another injury.
Holding the foot constantly over the accelerator pedal during a long car drive results in hip muscle imobilization, resulting in activation of trigger points in this muscle. Likewise, prolonged standing will have the same effect. SI joint dysfunction will perpetuate the trigger points.
Sitting on a wallet placed in a back pocket can cause impingement on this muscle and therefore produce referred pain in a sciatic-like distribution pattern.
By Ron Dunn