Which of the following statements are true?

A. The usual symptomatic lumbar disc herniation occurs in a posterolateral direction.

B. Approximately 95% of lumbar disc herniations occur at the L5–S1 or L4–L5 level.

C. Sciatica is a term used to denote pain felt along the distribution of the sciatic nerve.

DISCUSSION: Most symptomatic lumbar disc herniations do occur in a posterolateral direction, impinging on the overlying nerve root. About 95% of lumbar disc herniations occur at the L5–S1 or L4–L5 level. Approximately 4% occur at the L3–L4 level, and less than 1% at the L2–L3 or L1–L2 level. Sciatica is a term used to refer to pain along the course of the sciatic nerve. A ruptured lumbar disc typically causes low back pain and ipsilateral sciatica. The mechanical signs of a lumbar disc herniation include paravertebral muscle spasm, lumbar scoliosis, tenderness over one or more of the lower lumbar spines, limitation of low back motion, limitation of straight leg raising, and a positive popliteal compression test. Weakness of dorsiflexion of the foot is a neurologic sign, not a mechanical sign. Plain x-ray films of the spine do not demonstrate the presence and location of a lumbar disc herniation except in the rare instance of a calcified disc herniation. Myelography, CT, or MRI is needed to visualize the herniated disc.