What are the symptoms of sciatica?

Symptoms of Sciatica

Sciatica is characterized by pain radiating down the leg below the knee in the distribution of the sciatic nerve, which is more prominent than any accompanying low back pain. 1

Primary Pain Characteristics

• The hallmark symptom is lower limb pain that radiates below the knee and into the foot and toes, distinguishing it from simple low back pain 2
• Pain typically follows the posterior thigh, lower leg, and foot distribution of the sciatic nerve 3
• The pain may have a neuropathic character with burning, electric sensations, or dysesthesia 4
• Pain is often aggravated by spinal flexion and extension, walking, or running 4
• The leg pain is characteristically greater than any accompanying low back pain—this is a critical distinguishing feature 3

Neurological Symptoms

The American College of Physicians identifies three key nerve root distributions that produce specific patterns 5:

• L4 nerve root involvement: Knee weakness and diminished knee reflexes 5
• L5 nerve root involvement: Weakness of great toe and foot dorsiflexion 5
• S1 nerve root involvement: Foot plantarflexion weakness and diminished or absent ankle reflexes 5, 4

Sensory Changes

• Sensory deficits occur in the affected dermatome (L4, L5, or S1 distribution) 4
• Patients may experience numbness, tingling, or altered sensation along the nerve root distribution 4

Physical Examination Findings

• The straight-leg-raise test reproduces the sciatic pain when the hip is flexed with the knee extended between 30 and 70 degrees, though it has high sensitivity (91%) but modest specificity (26%) 1, 5
• The crossed straight-leg-raise test (pain when raising the unaffected leg) is more specific (88%) but less sensitive (29%) 5, 4

Red Flag Symptoms Requiring Urgent Evaluation

Be alert for symptoms suggesting cauda equina syndrome, which is a medical emergency 1, 4:

• Urinary retention or incontinence (urinary retention has 90% sensitivity) 1, 4
• Fecal incontinence 4
• Bilateral motor weakness of the lower extremities 1
• Saddle anesthesia (perianal or saddle numbness) 1
• Rapidly progressive or severe neurological deficits 4

Common Pitfalls

• Do not confuse referred pain from the lower back with true sciatica—true sciatica must radiate below the knee 1, 2
• A negative straight-leg-raise test does not exclude sciatica, as the combination of radicular pain pattern, dermatomal sensory changes, and motor weakness in a nerve root distribution establishes the diagnosis even without positive SLR 5
• Over 90% of symptomatic lumbar disc herniations occur at L4/L5 and L5/S1 levels 4