Protection from disc herniation is best provided by core strength and an awareness of body mechanics including good posture.

Disc herniation is frequently associated with age-related degeneration of the outer ring, known as the annulus fibrosus, but is normally triggered by trauma or straining by lifting or twisting.

Often, herniated discs are not diagnosed immediately, as patients present with undefined pains in the thighs, knees, or feet.

[citation needed] Symptoms may include sensory changes such as numbness, tingling, paresthesia, and motor changes such as muscular weakness, paralysis, and affection of reflexes.

[citation needed] It is possible to have a herniated disc without pain or noticeable symptoms if the extruded nucleus pulposus material doesn't press on soft tissues or nerves.

[4][5] A herniated disc in the lumbar spine may cause radiating nerve pain in the lower extremities or groin area and may sometimes be associated with bowel or bladder incontinence.

Compression of the cauda equina can cause permanent nerve damage or paralysis which can result in loss of bowel and bladder control and sexual dysfunction.

[citation needed] When the spine is straight, such as in standing or lying down, internal pressure is equalized on all parts of the discs.

The combination of membrane-thinning from stretching and increased internal pressure (14 to 21 bar (200 to 300 psi)) can result in the rupture of the confining membrane.

[9] Mutation in genes – such as MMP2 and THBS2 – that encode for proteins and enzymes involved in the regulation of the extracellular matrix has been shown to contribute to lumbar disc herniation.

[10][11] Disc herniations can result from general wear and tear, such as weightlifting training,[12][13] constant sitting or squatting, driving, or a sedentary lifestyle.

[17][18][19][20] Within athletic contexts, herniation is often the result of sudden blunt impacts against, or abrupt bending or torsional movements of, the lower back.

Herniations usually occur postero-laterally, at the points where the annulus fibrosus is relatively thin and is not reinforced by the posterior or anterior longitudinal ligament.

The rest of the spinal cord, however, is oriented differently, so a symptomatic postero-lateral herniation between two vertebrae will impinge on the nerve exiting at the next intervertebral level down.

Here, symptoms can be felt in the lower back, buttocks, thigh, anal/genital region (via the perineal nerve), and may radiate into the foot and/or toe.

[23] Symptoms of cervical herniations may be felt in the back of the skull, the neck, shoulder girdle, scapula, arm, and hand.

[27][28][29][30] There is evidence that points to a specific inflammatory mediator in back pain:[31][32] an inflammatory molecule, called tumor necrosis factor alpha (TNF), is released not only by a herniated disc, but also in cases of disc tear (annulus tear) by facet joints, and in spinal stenosis.

[37] Some authors consider that the term slipped disc is harmful, as it leads to an incorrect idea of what has occurred and thus of the likely outcome.

[citation needed] Diagnosis of spinal disc herniation is made by a practitioner on the basis of a patient's history and symptoms, and by physical examination.

[citation needed] The straight leg raise is often used as a preliminary test for possible disc herniation in the lumbar region.

[citation needed] Epidural corticosteroid injections provide a slight and questionable short-term improvement for those with sciatica, but are of no long-term benefit.

[61] When different forms of surgical treatments including (discetomy, microdiscectomy, and chemonucleolysis) were compared evidence was suggestive rather than conclusive.

A Cochrane review from 2007 reported: "surgical discectomy for carefully selected patients with sciatica due to a prolapsed lumbar disc appears to provide faster relief from the acute attack than non‐surgical management.

"[65] Regarding the role of surgery for failed medical therapy in people without a significant neurological deficit, a Cochrane review concluded that "limited evidence is now available to support some aspects of surgical practice".

[citation needed] Education should emphasize not lifting beyond one's capabilities and giving the body a rest after strenuous effort.

Signs of fatigue include shaking, poor coordination, muscle burning, and loss of the transverse abdominal brace.