Schmorl's Node: What It Is, How It Looks on X-ray and MRI

Sometimes a line reading "Schmorl's node" appears in an X-ray or MRI report. This is not the same as an ordinary disc herniation, and in most cases it is simply a finding on the image. We explain what this node is, where it comes from, and how to distinguish it from an intervertebral hernia.

What Schmorl's node is

Schmorl's node, or Schmorl's cartilaginous nodule, is a radiological term. It was described by the German physician Georg Schmorl in 1927. The mechanism is simple: the cartilage tissue of the endplate is pressed not outward but inward into the vertebral body, into the cancellous bone. The vertebral platform can be imagined as a lid against which the disc presses; in Schmorl's node, part of this lid collapses inward into the vertebra. Usually the node is located in the thoracic or lumbar spine — in the middle or lower part of the back.

Why it occurs

Most often the node is hereditary or appears in childhood during rapid growth: soft tissues stretch faster, bone lags behind, and voids remain in the vertebral body into which the endplate is eventually pressed. Congenital defects are associated with weakness and inferiority of cartilage tissue. Acquired Schmorl's nodes develop after spinal injuries — fractures, dislocations, subluxations, blows — as well as in degenerative diseases such as osteoporosis and osteoarthritis; more often in the elderly and senile age. Multiple nodes are, as a rule, small in size.

How Schmorl's node manifests

Most often it does not manifest at all. Nodes, as a rule, have no clinical manifestations, so they are found incidentally. In some cases the node may cause pain, more often in the lower back, less often in the legs. Large hernias should be a cause for concern: they thin the vertebral body, and this increases the risk of compression fracture under significant load. The node is also sometimes a weak spot through which an intervertebral disc may eventually collapse.

Schmorl's node on X-ray and MRI

The node is detected radiologically: on spinal radiography, X-ray computed tomography, and MRI. I will emphasize separately: a single X-ray image cannot be used to judge an ordinary disc herniation — that is a completely different matter.

How Schmorl's node differs from an intervertebral hernia

An ordinary disc herniation is when the soft tissue between the vertebrae bulges outward, into the spinal canal or neural foramen, and may press on nerves — hence pain, numbness, weakness in the arm or leg, although symptoms are not present in everyone. Schmorl's node goes in the opposite direction — inward into the vertebral body, not into the spinal canal or neural foramen, and usually has no clinical manifestations. Hence the difference in behavior: an ordinary hernia may hurt, while Schmorl's node usually stays silent and remains a finding on the image. These are different mechanisms: in the first case the disc is displaced, in the second the endplate collapses.

When to see a doctor

If the report contains Schmorl's node and nothing hurts, show the report to a doctor; they will assess whether further steps are needed. If the back hurts, the pain does not resolve within several weeks, there is numbness or weakness in the leg or arm, high temperature, unexplained weight loss, swelling on the back, or pain that is worse at night — an examination is needed. At the appointment the doctor checks:

• the presence of numbness or loss of sensation;
• muscle reflexes — slowed or absent;
• muscle strength;
• posture and spinal curvature;
• the ability to bend the spine.

Small nodes usually do not require special treatment; in case of pain syndrome, the tactics are determined by the doctor.

Schmorl's node by itself is not a reason to call an ambulance. Call 103 or 112 if, against the background of back pain, numbness has appeared around the perineum or genital organs, urination or control over urination and defecation has been lost, sensation has been lost in one or both legs, and also if the pain arose after a serious accident or injury.

The material is for reference and does not replace a doctor's consultation: show the images and report to a specialist who will assess the picture as a whole.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer