Numbness Radiating from the Buttock Down the Leg: Sciatica Tests and Recovery Time

Last updated: 2026-10-23

Numbness That Starts in the Buttock and Travels Down to the Calf

When numbness travels from the buttock down to the calf, you are experiencing sciatica, a term for pain and numbness that radiate along the path of the sciatic nerve. Sciatica is not the name of a single specific disease; it is a sign that pressure or inflammation has developed somewhere along the nerve pathway running from the lower back to the toes.

For example, an office worker in their 50s may feel a heaviness in one buttock after sitting for long hours all day, and by evening feel numbness spreading to the back of the thigh and the outer calf. In cases like this, coughing or sneezing can also send a sudden, sharp pain down the leg.

The sciatic nerve is the thickest nerve in the body, formed where nerve roots from the lower back and sacrum join together. It passes deep through the buttock, runs down the back of the thigh, and continues all the way to the calf and foot. Because of this, if any single point along this path is physically compressed or becomes sensitized by nearby inflammation, pain, numbness, pulling sensations, and burning can appear one after another along the nerve's course. These sciatica symptoms usually concentrate in one leg rather than affecting both.

Numbness Can Start in Four Different Places

In a herniated lumbar disc, the disc (the soft cartilage between the vertebrae) bulges backward and presses directly on the nerve root that runs from the lower back down into the leg. Sitting in a chair for a long time, or coughing and sneezing, which raise abdominal pressure, tends to make the leg numbness noticeably worse. In spinal stenosis, by contrast, the ligaments thicken and bone grows with age, narrowing the very passage the nerve travels through. Standing and walking for a long time makes the legs feel numb and heavy as if they were about to burst, but squatting down to rest for a moment widens the passage and the symptoms settle.

Sometimes the problem starts not in the lower back but in the buttock itself. In piriformis syndrome, the piriformis muscle deep in the buttock tightens or swells and irritates the sciatic nerve running nearby. In people with piriformis syndrome, the longer they sit on a hard chair or in the driver's seat, the more the deep part of the buttock aches, and the back of the thigh may also pull strongly.

Sacroiliac joint pain can cause similar symptoms even when no nerve is directly compressed. When a problem develops in the sacroiliac joint, where the sacrum and the ilium of the pelvis meet, referred pain spreads into the buttock and the back of the thigh and can feel just like sciatica. However, sacroiliac joint pain mostly stays in the thigh above the knee rather than extending down into the calf. Symptoms can also become more complicated when two causes appear at the same time, such as a herniated lumbar disc together with sacroiliac joint pain.

What Can a Leg-Raising Test Tell Us?

At Ansim Teunteun Pain Clinic, we first ask specifically when the numbness started and how far down the leg the pain spreads. At the start of the exam, we identify which situation makes the symptoms most noticeable: sitting, walking, or coughing.

Next, we perform the straight leg raise test, in which you lie flat on your back on the exam table and the leg is slowly raised with the knee kept straight. If raising the leg roughly 30 to 70 degrees off the table reproduces the radiating pain in the buttock and leg that you usually feel, it means a nerve root in the lower lumbar spine is being stretched and irritated. A review that pooled studies using surgical findings as the reference standard found that the straight leg raise test had a high sensitivity of 0.91 but a low specificity of 0.26 (Devillé WL et al., 2000). In addition, individual physical exam tests alone are not enough to accurately identify a nerve root lesion caused by a herniated disc (the soft cartilage between the vertebrae). The evidence for simply combining several tests was also limited (van der Windt DA et al., 2010).

For this reason, we do not rely on the leg-raising test alone; we also perform a neurological exam. We compare both legs for the strength of pulling the big toe up toward the face and the strength of rising onto the toes with the heel lifted, and we check whether skin sensation on the outer calf, the top of the foot, and the sole differs from the other side. When strength or sensation is reduced in a specific area like this, we can narrow down which lumbar nerve root is affected.

If signs of lumbar nerve root irritation are not clear, we press directly on the deep part of the buttock to check for tenderness and examine whether rotating the hip joint in specific directions reproduces the pain. In fact, an analysis of 97 case reports covering 212 patients with piriformis syndrome found that 50.5% of them were diagnosed based on clinical exam findings like these (Monteleone G et al., 2025).

Along with the physical exam, we also perform X-rays and ultrasound diagnosis as needed. An X-ray evaluates the structure and alignment of the bones, showing the overall alignment of the lumbar spine, the spacing between the vertebrae, areas where bone has overgrown, and whether an upper lumbar vertebra has slipped forward. Ultrasound diagnosis uses sound waves that are harmless to the body to observe the condition of tissue in real time while joints and muscles move. With it, we look at the piriformis muscle deep in the buttock, the tissue around the sciatic nerve, and the ligaments and muscles that support the sacroiliac joint. If you bring MRI, CT, or X-ray images taken previously at another facility, we compare them closely with your current pain pattern and physical exam findings to determine the cause.

When Buttock Sensation Dulls and Urination Becomes Difficult

Most leg numbness is managed with outpatient care and stepwise treatment, but there are also warning signs that call for going to the emergency room without delay. If the skin around the buttocks, groin, and anus feels dull as though it belonged to someone else, or if bladder and bowel control changes, with urine not passing easily and urine or stool becoming hard to hold in, this is a warning sign of cauda equina syndrome, in which the bundle of nerves below the lower back is strongly compressed all at once. When symptoms suggesting cauda equina syndrome appear, an emergency evaluation on that same day is needed to prevent nerve damage.

Even without urinary problems, a prompt neurological evaluation is needed if foot drop develops, where lifting the top of the foot becomes difficult and the toes drag on the ground while walking, or if leg weakness progresses quickly. Also, when numbness newly appears in both legs rather than one, the urgency of care is judged by whether it comes with changes in leg strength or with urinary and bowel symptoms. When a decline in nerve function progresses like this, a detailed evaluation with MRI is needed to confirm exactly where the nerve is compressed.

If leg pain comes with a fever of unknown cause or unexplained weight loss, we run tests to find the cause, including infection or a tumor around the spine. Even without an emergency or whole-body symptoms like these, if numbness in the buttock and leg lasts more than two weeks, or if the pain makes it hard to walk on level ground or keeps you from sleeping at night, you should be examined in an outpatient visit to confirm the exact cause.

When Does Leg Numbness Start to Ease?

Sciatica often improves gradually over several weeks to several months, and the actual pace of recovery depends on the cause, how long the symptoms have lasted, and how much nerve function has declined. Even after the sharp, radiating pain eases first, dull numbness or reduced sensation can remain for a longer time. The ATLAS cohort study, which followed 609 primary care patients with back-related leg pain, found that 55% of patients had a 30% or greater reduction in disability score after 12 months, and the longer the leg pain had lasted before care, the lower the outlook for recovery tended to be (Konstantinou K et al., 2018).

Dr. Jinyeol Kwon, the head physician of Ansim Teunteun Pain Clinic, was once a patient who received 15 injections over more than a year for severe cervical disc pain. Drawing on this experience, at Ansim Teunteun Pain Clinic we do not stop at calming the immediate pain; we set our treatment goal as restoring the body's movement so that you can return to ordinary daily life.

In the acute phase, when leg pain is severe enough to keep you from sleeping at night or even walking, we perform a nerve block. A nerve block is a treatment that delivers medication precisely around the compressed, inflamed nerve while the position of the bones and nerve passages is checked with a C-arm, a real-time imaging device. The procedure usually takes about 5 to 10 minutes, and after resting while your condition is checked, you go home the same day. At Ansim Teunteun Pain Clinic, we usually perform nerve blocks 1 to 3 times at 1- to 2-week intervals and then evaluate how much the pain has decreased and how walking function has changed.

Once the acute pain has settled, we continue with spinal adjustment to correct the misalignment of the lower back and pelvis and improve joint movement. Spinal adjustment follows a baseline schedule of 1 to 2 sessions per week for 4 to 8 weeks in total, adjusted to your recovery. Alongside this, rehabilitation therapy that builds strength in the weakened muscles around the lower back and helps you carry out daily movements without strain runs 2 to 3 times per week over a 4- to 12-week baseline. For myofascial pain that lingers around the lower back and buttocks even after the nerve pain has decreased, we apply extracorporeal shockwave therapy 3 to 5 times at 1-week intervals and watch how the tissue responds. If piriformis syndrome is the cause, we release excessive tension in the pelvic and buttock muscles through corrective manual therapy and manual therapy in which the physician takes part directly, and we combine these with a nerve block when pain levels are high and with extracorporeal shockwave therapy when deep myofascial pain remains.

While conservative treatment continues, a protruding disc (the soft cartilage between the vertebrae) can sometimes shrink on its own. According to a review that pooled multiple studies, the rate of spontaneous regression of the disc (the soft cartilage between the vertebrae) seen on imaging during conservative treatment was 96% for sequestration, where a fragment has broken off, 70% for extrusion, 41% for protrusion, and 13% for bulging (Chiu CC et al., 2015).

In a randomized study of 283 patients who had severe sciatica for 6 to 12 weeks, the group that had early surgery saw leg pain decrease faster than the group that received prolonged conservative treatment (Peul WC et al., 2007). The prolonged conservative treatment group in this study included a strategy of watching the course and having surgery only when truly needed, and at one year, the proportion of patients who felt they had recovered was the same in both groups at 95% (Peul WC et al., 2007). Accordingly, at Ansim Teunteun Pain Clinic, we discuss surgery when leg pain continues and interferes with daily life, or when leg strength gradually declines, despite a sufficient period of non-surgical treatment.

Jinyeol Kwon · Anesthesiology and Pain Medicine Specialist · Ansim Teunteun Pain Clinic

References

Devillé WL, van der Windt DA, Dzaferagić A (2000). The test of Lasègue: systematic review of the accuracy in diagnosing herniated discs.. Spine (Phila Pa 1976). PMID: 10788860
van der Windt DA, Simons E, Riphagen II (2010). Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain.. Cochrane Database Syst Rev. PMID: 20166095
Monteleone G, Stevanato G, Alimandi M (2025). Piriformis syndrome: a systematic review of case reports.. BMC Surg. PMID: 41068685
Konstantinou K, Dunn KM, Ogollah R (2018). Prognosis of sciatica and back-related leg pain in primary care: the ATLAS cohort.. Spine J. PMID: 29174459
Chiu CC, Chuang TY, Chang KH (2015). The probability of spontaneous regression of lumbar herniated disc: a systematic review.. Clin Rehabil. PMID: 25009200
Peul WC, van Houwelingen HC, van den Hout WB (2007). Surgery versus prolonged conservative treatment for sciatica.. N Engl J Med. PMID: 17538084

Frequently Asked Questions

Q. Can it still be sciatica if my back doesn't hurt and only my leg feels numb?

Even without back pain, numbness that radiates from the buttock down the leg can still be sciatica. At Ansim Teunteun Pain Clinic, we ask how far the numbness extends and which postures make it worse, and we test nerve function to distinguish lumbar nerve root irritation from other causes.

Q. If I already have a previous lumbar spine MRI, do I need to get another one?

At Ansim Teunteun Pain Clinic, we compare your previous MRI images and radiology report with your current symptoms and examination findings to decide whether a new scan is needed. If the location of your numbness has changed or your strength has declined since the scan, it helps to also tell us when that change began.

Q. If pain decreases after a nerve block but numbness remains, what happens next?

If numbness remains, it helps to keep a record of the numb area, any changes in sensation, and difficulty walking, separately from how much the pain has decreased. At Ansim Teunteun Pain Clinic, we compare this record with nerve function test results to decide whether further treatment is needed, and we do not increase the number of injections simply because numbness remains.

Q. How should I manage walking and desk work while sciatica is healing?

Break walking into short sessions, stopping before the numbness gets worse, and when working at a desk, get up partway through to change position. If numbness spreads more widely or lasts longer after an activity, reduce the duration and intensity of the next activity, and keep a record of the posture and length of time that brought on the symptoms.