A recent Nature Communications article sheds light on how fluid drainage systems may worsen jaw pain in the 5 to 8 percent of Americans affected by temporomandibular joint disorders.

PROBLEMS WITH JAW JOINTS and muscles — also known as temporomandibular disorders (TMD) — cause pain in the jaw, face or ears, as well as clicking, popping or locking of the jaw.

Even though they impact 5-8 percent of Americans, TMJ problems are not well understood. There are dozens of subcategories of problems that cause joint pain.

“Pain is the major reason why patients go to the hospital,” Professor Jianfu Chen says. “It’s actually the second most common musculoskeletal pain, next to low back pain.”

Better Understanding of TMJ Issues

Now, a new article by Chen and colleagues — titled “Identification of synovial lymphatic system in the temporomandibular joint and their roles in arthritis” — is shedding light on some of the issues of TMD.

The researchers used genetically modified mice to identify, for the first time, a lymphatic vascular system in the synovial tissue of the TMJ. The researchers showed that when the synovial fluid — the lubricating fluid located in one’s movable joints — doesn’t clear correctly, it can lead to dysfunction in the lymphatic system, which drives TMJ arthritis, bone loss and pain. The findings were published in April 2026 in the journal Nature Communications.

Even though the disease is devastating, Chen says that it’s rarely studied — his group is pioneering research into how the lymphatic system works in the jaw region.

“We noticed that, in dental school or medical school, there’s very little covered in terms of the temporomandibular joint,” says Chen, who is the director of Ostrow’s craniofacial biology graduate program and interim director of the Center for Craniofacial Molecular Biology. “There’s many people who study lymphatic vessels in the heart or lungs, but the craniofacial region has remained largely unexplored.”

A Different Type of Treatment?

The studies that have been done on the lymphatic system generally focus on how cytokines and chemokines — small, signaling proteins secreted by immune cells to regulate immunity and inflammation — are generated to trigger pain. The new study looks at the same questions from a different angle, Chen says: “We are thinking about what exists in our body to clear them.”

The findings that there is a fluid-regulating system that impacts pain could eventually help patients find relief from the disorders associated with the joint. Chen sees a day in the future where treatments could specifically target the lymphatic vascular system to lessen joint degeneration or pain.

For Yang Shu, a doctoral student and first author of the paper, the research was a way to expand his training.

“As a young trainee, it’s rare to have an opportunity for training and publication like this,” he says. “I think this is a very good starting point for my scientific growth and career development.”

Chen hopes that the publication opens new routes to understanding how the lymphatic system and synovial tissue interact with TMJ disorders.

“This is a broader-impact journal,” Chen says. “Hopefully, it encourages more TMJ researchers and brings TMD research to a broader scientific audience.”