We talk a lot about leg pain stemming from a pinched or irritated nerve in the lower back. And, indeed, that’s what our physicians are traditionally taught in medical school—a pinched nerve in the lumbar spine typically presents as a symptom in the leg. However, what if you have some butt pain but no pain or other symptoms in the leg? Does this mean it couldn’t be a pinched nerve? Not so fast. Turns out a pinched low back nerve doesn’t always have to be accompanied by leg symptoms.
Let’s start by taking a look at how the back is structured.
How the Back Is Structured
The supporting structure of the back is the spinal column, and intricate part of the musculoskeletal system made up of 24 vertebrae (backbones) placed one atop the other. The spinal column stretches from the base of the skull all the way down to the tailbone. Between each vertebral level at the front of the spinal column rests an intervertebral disc intended to provide cushioning so the bones don’t rub together and absorb shock during movement and activity. Along the back of the spine, each vertebra meets the next at the facet joints, which have cushioning cartilage and provide flexibility and allow for a variety of movements.
Protected inside the spinal column is a large nerve bundle called the spinal cord. Nerves branch off the spinal cord all along the spinal column through openings called foramina around the facet joints. These nerves transmit signals to and from the brain and every part of our body. The low back nerves, for example, exit the lumbar and sacral regions of the spinal column and supply our lower limbs, sending signals back and forth between our brain and as far out as the tips of our toes.
What Is a Pinched Low Back Nerve?
A pinched low back nerve really is exactly what it sounds like: something has caused the nerve to become constricted. There are, however, many different things that can cause a pinched low back nerve. A foramen, one of those holes at the back of the spinal column that the nerves travel through, can become narrowed. This is called foraminal stenosis and is a common cause of pinched nerves. You can learn more about it by watching Dr. Centeno’s video below:
Pinched nerves can also result from arthritis in the facet joints, which can narrow the space, constricting those nearby nerves. In addition bulging or herniated discs can also irritate and put pressure on the nerve. Regardless of the reason for the pinched nerve, the key to treating it is to treat what’s causing it.
In any case, when there is a pinched low back nerve, the traditional indicator has been leg pain or some other symptom in the leg. However, one study seems to suggest what we’ve observed for many years: this isn’t always the case.
Low Back Pinched Nerves and the Distribution of Pain
One study investigated the distribution of pain (e.g., low back, legs, butt) in over 1,800 patients with chronic low back disorders. Where it was determined that nerve pain was the primary issue, whether patients had leg symptoms or not, most with butt pain did have low back nerve issues. This study suggests that old-school thinking that you must have leg symptoms if you have a pinched nerve simply isn’t true.
What does this tell us exactly? That many patients with pinched nerves aren’t being diagnosed as such because they don’t have the textbook leg symptoms to go along with it. Many of these patients have butt pain, but no leg pain, and when an MRI clearly shows a pinched low back nerve but there’s no leg pain, the pinched nerve isn’t being diagnosed as a reason for the butt pain. A pinched nerve is particularly likely if you have some low back pain that reaches into your butt area. If you have butt pain, with or without leg symptoms, make sure your doctor is checking for a pinched nerve.