The three types of vertebral compression fractures are wedge, biconcave, and crush fractures. Each is classified by the shape the vertebral body takes after it collapses, and they differ in which part of the bone fails under pressure. Globally, about 7.5 million new vertebral fractures occur each year, with falls being the leading cause, particularly in older adults.
Wedge Fractures
Wedge fractures are the most common type. The front (anterior) portion of the vertebral body collapses while the back stays intact, creating a wedge shape when viewed from the side. This happens because the front of the spine bears more compressive load during everyday movements like bending forward. In people with osteoporosis, even minor stress like lifting a grocery bag or coughing forcefully can cause the weakened bone to buckle at the front edge.
When multiple wedge fractures stack up across several vertebrae, each one tilts the spine slightly more forward. Over time, this accumulation produces a rounded, hunched posture known as kyphosis, sometimes called a “dowager’s hump.” This forward curvature can crowd the chest and abdomen, making it harder to breathe deeply or eat comfortably.
Biconcave Fractures
Biconcave fractures collapse through the center of the vertebral body while both the front and back edges remain relatively intact. The top and bottom surfaces of the bone cave inward, giving the vertebra an hourglass or bow-tie shape on imaging. This pattern is sometimes called a “codfish vertebra” because the resulting shape resembles the vertebrae found in codfish. The term was coined in the 1940s by endocrinologist Fuller Albright while studying bone loss in postmenopausal women.
The collapse happens because the spongy bone in the interior of the vertebral body is weaker than the denser bone at the edges. As the discs above and below press inward, they create smooth, squared-off depressions in the endplates. Biconcave fractures tend to cause less dramatic changes in spinal alignment than wedge fractures, but they still reduce overall height and signal significant bone weakness.
Crush Fractures
Crush fractures are the most severe type. The entire vertebral body collapses uniformly, losing height across both the front and back. Rather than tilting into a wedge or bowing inward, the vertebra flattens. These fractures typically result from greater force or more advanced bone loss and cause the most significant height reduction of the three types.
Because the whole structure compresses, crush fractures carry a higher risk of complications like nerve compression and chronic pain. They can also destabilize the spine more than the other types, since neither the front nor back wall retains its normal height to support the vertebrae above.
Causes and Risk Factors
In younger people, compression fractures usually require high-energy trauma like a car accident, a fall from significant height, or a sports injury. In older adults, the picture is very different. Bones weakened by osteoporosis can fracture under forces as minor as stepping off a curb or sneezing. Falls are the leading cause worldwide, with a rate of about 58 per 100,000 people. Road injuries and other mechanical forces account for most of the remaining cases.
Cancer that has spread to the spine can also weaken vertebral bone enough to cause pathological compression fractures. These fractures behave differently from osteoporotic ones and usually require additional evaluation and treatment focused on the underlying disease.
Symptoms Across All Three Types
Regardless of the fracture type, the most common symptom is sudden back pain that improves with rest and worsens with movement. You might also notice tenderness directly over the fracture site, muscle spasms, and difficulty standing, walking, bending, or twisting. Some people feel tingling or numbness if the collapsed bone pinches a nearby nerve.
One of the most telling signs is a loss of height. Each fractured vertebra can lose several millimeters, and multiple fractures over time can reduce your standing height by an inch or more. Long-term complications include chronic pain, progressive spinal curvature, future fractures in adjacent vertebrae, and in severe cases, problems with bladder or bowel control.
Many compression fractures, particularly mild wedge or biconcave types, go undiagnosed because people attribute the pain to normal aging or muscle strain. Studies estimate that roughly two-thirds of vertebral fractures never come to clinical attention.
How Compression Fractures Are Diagnosed
Standard X-rays can reveal the characteristic shape changes of each fracture type. However, X-rays cannot tell you whether a fracture is fresh or old. MRI is the preferred tool for making that distinction because it detects bone marrow swelling that indicates active healing, making it useful for identifying acute fractures that need treatment. CT scans are typically reserved for cases where MRI results are inconclusive or when more detailed bone anatomy is needed for surgical planning.
Treatment Options
Most compression fractures heal with conservative care: pain management, rest, and a gradual return to activity over six to twelve weeks. Some people wear a brace to limit spinal motion during healing, though prolonged bed rest is discouraged because it accelerates bone loss.
When pain persists despite conservative treatment, two minimally invasive procedures can help. In vertebroplasty, bone cement is injected into the fractured vertebra to stabilize it. In kyphoplasty, a small balloon is first inflated inside the vertebra to restore some of the lost height before the cement is placed. Both procedures effectively reduce pain and improve function. Clinical trials have shown that vertebroplasty provides substantial pain relief compared to placebo, with benefits lasting at least six months for acute fractures and up to twelve months for chronic painful fractures. Kyphoplasty offers a similar level of pain relief with a lower rate of cement leaking outside the vertebra, which is its main safety advantage.
For any type of compression fracture linked to osteoporosis, treating the underlying bone loss is essential. Without it, the weakened spine remains vulnerable to additional fractures in the months and years that follow.