It is no secret that infants have extra bones than adults: Whereas newborns can have 275 to 300, with smaller bones fusing and hardening to create bigger bones as the kids get older, most adults have solely 206. (Having tinier, softer bones provides infants the additional flexibility they should curl up within the womb and make their approach by way of the beginning canal.)
However is it doable for adults to have additional bones?
Nonetheless, there typically aren’t apparent indicators that somebody has greater than the everyday variety of bones.
“It is extremely simple to not know that somebody has an adjunct bone,” Dr. Vandan Patel, an orthopedic surgeon on the Institute for Foot and Ankle Reconstruction at Mercy Medical Middle in Baltimore, informed Dwell Science. More often than not, accent bones don’t trigger any signs. “Oftentimes, we study that somebody has an adjunct bone after they have an X-ray finished for one thing unrelated and they’re discovered by the way,” he defined.
Even when accent bones are seen on X-rays, they’re continuously missed or misinterpreted as fracture fragments or age-related adjustments, mentioned Eren Ogut, an affiliate professor of anatomy at Istanbul Medeniyet College. All in all, “research counsel that they happen in roughly 10 to 30% of the final inhabitants,” however “their true prevalence is probably going increased than generally appreciated,” Ogut informed Dwell Science.
Accent bones are widespread within the foot and ankle, Patel mentioned. The commonest accent bone is called the os trigonum, he mentioned. “That is seen in as much as 10 to 25% of individuals,” Patel famous. “It’s situated at the back of the ankle joint. It could possibly trigger ache, particularly when pointing the toes and the ankle down, akin to in a ballet dancer in en pointe place.”
One other widespread accent bone is named the os tibiale externum, also referred to as accent navicular. “It’s seen in as much as 12% of the inhabitants,” Patel mentioned. “It’s situated on the within of the foot, subsequent to the conventional navicular bone. Generally the navicular bone seems enlarged. It could possibly trigger ache within the arch and is usually seen with flat-foot deformity.”
Medical doctors additionally learn about various unusual accent bones, typically by way of research of cadavers or medical imaging, Ogut mentioned. One instance is the os acetabuli, an adjunct bone of the hip which may be related to hip ache, he famous. This accent bone is seen in lower than 5% of the final inhabitants, Ogut famous in a 2025 evaluate article within the Bratislava Medical Journal.
Generally it is doable to own accent ribs. As much as 1% of individuals have one and even two additional bones of their neck at beginning often known as cervical ribs, in line with the Cleveland Clinic. This uncommon bone would not resemble a typical rib; it may be extra vertical or diagonal as an alternative of horizontal just like the ribs within the chest. More often than not, cervical ribs trigger no issues, however they will result in ache or weak spot within the arm. In such circumstances, bodily remedy or drugs can assist. A surgeon can even take away them, as they do not serve a objective, the clinic famous.
