Home / Conditions / Back pain / Lower back pain
The lumbar spine carries the weight of everything above it while still having to bend and twist. That combination is why most back pain happens here — and why most of it settles.
This page covers the lower back specifically. For neck and upper back, and for how the different kinds of back pain behave, see back pain.
Five lumbar vertebrae sit between the rib cage and the pelvis. Above them, the thoracic spine is braced by the ribs and barely moves. Below them, the sacrum is fused solid. The lumbar spine is the only part of the lower trunk that both carries load and bends.
Everything you do with your back — lifting, twisting, sitting forward — concentrates at those five joints, and particularly at the lowest two, where the spine meets the pelvis. That is why L4–L5 and L5–S1 account for the great majority of disc problems.
This single question separates the two situations, and they are managed differently.
Pain reaching into the buttock or the back of the thigh sits in between and can come from either. Pain that goes past the knee, into the calf or foot, is the one that most reliably indicates nerve involvement.
Where symptoms travel into the leg, the part of the leg and foot involved usually identifies the level — often before any scan.
| Nerve root | Symptoms reach | Weakness shows as |
|---|---|---|
| L3–L4 | Front of the thigh, inner shin | Straightening the knee, stairs |
| L5 | Outer shin, top of the foot, big toe | Lifting the foot — see foot drop |
| S1 | Back of the calf, sole and outer foot | Pushing off, standing on tiptoe |
L5 and S1 account for most cases, which follows from those being the busiest joints. If you can say which part of the foot is affected, you have given the most useful part of the history.
The left side shows where the problem is: a disc at L4–L5 that has herniated, with its soft centre pushing through the outer ring and pressing on the nerve root leaving at that level.
The right side shows where it is felt. The nerve continues down through the buttock, the back of the leg and into the foot, and symptoms appear anywhere along that course — which is why the back can ache mildly while the calf is the part that really hurts.
This is why the foot matters more than the back in the history. The pain you notice most is often furthest from the problem, and the part of the foot involved is what points to the level.
Lower back pain is rarely an emergency. These are the exceptions, and the first group in particular is measured in hours rather than days:
Call us on +65 8849 0677 and describe the symptom. We will see you the same day and arrange imaging if it is needed.
If we are closed, go to an emergency department. We are shut on Sundays and after 1pm on Saturdays. For the first symptom on that list, do not wait for us to open.
Call +65 8849 0677A strained muscle and a torn disc can feel the same. The structures of the lower back share nerve supply, so the brain localises pain here poorly. Both produce inflammation and spasm in the same area. The difference is what happens next: muscle and ligament heal quickly, while a torn disc may take months. That is one reason an episode lasting longer than expected is worth assessing.
Examination before imaging. Which movements provoke it, whether nerve function is affected, and whether the pattern fits the level the symptoms suggest.
Scans find things that are not causing your pain. Disc bulges and degeneration appear routinely in people with no symptoms and become more common with age — which is why an early scan in ordinary lower back pain tends to confuse rather than clarify.
Most people improve without injections or surgery. Treatment moves in steps, and the first one is the best supported.
Staying active within your limits shortens an episode; lying still lengthens it and weakens the muscles that support the spine. Modify the specific loads that provoke it — prolonged sitting above all — rather than stopping altogether.
Strengthening, movement retraining and posture work. More effective when it targets the specific pattern than as generic core exercises, which is why the assessment comes first.
Anti-inflammatories, and briefly a muscle relaxant where spasm is limiting. Where pain is nerve-related, ordinary painkillers help little and medication aimed at nerves is used instead.
Image-guided injections to the facet joints, the epidural space or a nerve root. Both diagnostic and therapeutic — the response confirms whether the level treated is the level responsible, which matters before any surgical decision.
Few people with lower back pain need surgery. It is considered where a nerve is compressed with weakness or unrelenting leg pain, where a segment is unstable, or where narrowing has not responded to anything else.
Decompression, discectomy, foraminotomy, disc replacement and fusion are performed here — see spine surgery. Surgery treats structure. It does not treat pain with no structural explanation, and offering it in that situation is how people end up worse.
Lower back pain is the condition where this question comes up most, because it can arise from a nerve or from a structure, and those sit on different sides of the same speciality.
Leg pain, numbness, weakness, sciatica, a disc pressing on a root, stenosis narrowing the canal.
A neurosurgeon trains on the nervous system first and the spine second, so decompressing nerves is the centre of the work rather than the edge of it. Dr Mathew Tung.
Instability, a vertebra slipping, deformity, fracture, a segment that needs fusing or reconstructing.
An orthopaedic spine surgeon trains on the musculoskeletal system first, so alignment, load and mechanical reconstruction are the centre of the work. Dr Lim Heng Hing.
The overlap is large. Both perform discectomy, decompression and fusion, and for most lower back problems either is entirely appropriate. The point is not that you must pick correctly.
The point is that you usually cannot pick, because you do not yet know which kind of problem you have. That is what the assessment establishes — and having both surgeons in the same clinic means the answer is not shaped by whichever one you happened to book. If it turns out to be the other kind, that is a conversation down the corridor rather than a new referral and another wait.
More on how the two differ: neuro spine and orthopaedic spine surgery.
If there are none of the urgent signs above, four to six weeks of sensible self-management is reasonable. Sooner if pain travels below the knee, or if there is numbness or weakness.
Briefly at most. Bed rest is not recommended for ordinary lower back pain — it lengthens the episode and weakens the supporting muscles. Staying active within your limits is better supported than anything else here.
It means a nerve is likely involved, which is worth assessing, but it is not usually an emergency. Most leg pain from a compressed nerve improves over weeks. Weakness, or symptoms in both legs, changes that.
Usually not at first. Scans show changes in people with no pain at all, so early imaging in ordinary lower back pain often adds confusion. It becomes useful where nerves are involved or where treatment decisions depend on it.
Most episodes resolve. Where there is underlying degenerative change, the aim is managing symptoms and reducing recurrences rather than reversing the changes — and that is usually very achievable.
For most lower back problems either is appropriate, and the overlap between them is substantial. Nerve problems lean neurosurgical; instability, deformity and fractures lean orthopaedic. Since you cannot usually tell which you have before being assessed, the practical answer is to see whoever can establish that — and both work from this clinic.
No. Bring any imaging, and note whether pain travels into a leg and how far, what makes it better or worse, and what you have already tried.
Back pain · Sciatica · Slipped disc · Spinal stenosis · Annular tear · Spondylolisthesis · L4–L5 herniation · Spine surgery
Most lower back pain does not need surgery. It does need to be understood — particularly if it is travelling into a leg.
