Sciatica: Why the Pain Travels Down Your Leg — and How to Fix It

Sciatica is a symptom, not a diagnosis. Understanding the root cause is the key to lasting relief. We break down the anatomy and treatment options.

Sciatica is one of the most commonly misunderstood conditions in musculoskeletal medicine. It isn't a diagnosis — it's a description. A description of what happens when the sciatic nerve, the largest nerve in the human body, is irritated anywhere along its course from the lumbar spine through the gluteal region and down the back of the leg.

The anatomy of the sciatic nerve

The sciatic nerve forms from the L4, L5, S1, S2, and S3 nerve roots — five spinal nerve contributions that merge in the sacral plexus and exit the pelvis beneath the piriformis muscle. It runs through the deep gluteal region, down the posterior thigh, and branches into the tibial and common peroneal nerves at the knee. Any structure that compresses or irritates this nerve — at any point along this path — can produce the classic sciatic pattern: pain, numbness, tingling, or weakness anywhere from the buttock to the foot.

Most common causes of sciatica

• Lumbar disc herniation (most common): nucleus pulposus pressing directly on a nerve root at L4-L5 or L5-S1

• Lumbar spinal stenosis: age-related narrowing of the spinal canal or foramina, most common in people over 50

• Piriformis syndrome: the piriformis muscle, which the sciatic nerve passes through or beside, becomes hypertonic and compresses the nerve

• Degenerative disc disease: collapsed disc height reduces foraminal space, pinching exiting nerve roots

• Spondylolisthesis: one vertebra slips forward on another, narrowing the space for nerve roots

• Sacroiliac joint dysfunction: SI joint inflammation can mimic or contribute to sciatic symptoms

How chiropractic diagnosis works

A thorough sciatic evaluation at GraceSpine includes dermatome testing (mapping sensation loss patterns), deep tendon reflexes (assessing nerve root integrity), straight leg raise and Slump test (provocative orthopedic tests), muscle strength testing, and a detailed history. This clinical picture identifies which structure is responsible — disc, foramen, piriformis, or SI joint — and shapes the entire treatment approach.

Chiropractic treatment options

• Spinal manipulation: restores motion to restricted lumbar and pelvic joints, reducing nerve root irritation

• Flexion-distraction: gentle traction-based technique that creates negative intradiscal pressure, encouraging herniated nucleus retraction

• Piriformis release: targeted soft tissue therapy and stretching protocols for piriformis syndrome

• SI joint manipulation: precise adjustment of the sacroiliac joint to restore pelvic symmetry

• Rehabilitation: progressive core stabilization, sciatic nerve mobilization, and hip strengthening to prevent recurrence