What does periosteum mean?
The periosteum is the dense, fibrous membrane that covers the outer surface of most bones. It is richly supplied with blood vessels, helping nourish the bone, and it provides a surface to which tendons, ligaments, and muscles can attach. The periosteum is absent over the smooth surfaces of bones that articulate in joints, where cartilage and the joint capsule provide the covering instead. In medicine, the term appears in descriptions of fractures, bone infections, and surgical procedures. During healing, new bone develops beneath the periosteum. Periosteitis is inflammation of this membrane, while periosteal describes structures associated with it. Although the word may resemble peritoneum, the two terms refer to entirely different tissues: one surrounds bone, and the other lines the abdominal cavity.
nounThe tough, fibrous membrane that covers the outer surface of a bone, except at its articular surfaces, where it forms part of the joint capsule. It contains blood vessels and provides attachment for tendons and ligaments.
- The fibrous membrane covering the outer surface of a bone.
"The surgeon carefully separated the periosteum from the bone to expose the fracture."
"New bone forms beneath the periosteum during fracture healing."
"The infection had spread through the periosteum to the underlying bone."
The plural periostea is standard in anatomical and surgical usage; periosteums is also encountered but is less usual.
"The operation exposed the periostea overlying the affected bones."
The periosteum is bone's living outer coat: a vascular membrane that helps nourish the bone and anchors muscles and ligaments.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does periosteum come from?
The word comes through Latin from Greek periosteon, meaning the membrane surrounding a bone. Its elements are the Greek prefix peri-, meaning around or surrounding, and osteon, meaning bone. The same Greek root underlies modern terms such as osteology, osteotomy, and osteoporosis, all concerned with bones or their structure.
Related word forms
How periosteum is actually used
This is a specialist anatomical term used chiefly in medicine, surgery, biology, and anatomy. It is normally used in the singular for the membrane as a general structure; the plural is periostea. The related adjective is periosteal.
Easily confused with periosteum
The periosteum covers the outside of bones, whereas the peritoneum lines the inside of the abdominal cavity.