a tough but bendable tissue that eventually hardens into bone. (Adults retain some cartilage, mainly in their joints.) But flat bones – like the skull, collarbone, some facial bones, and parts ...

The sternum, or breastbone, is the flat bone where the ribs meet. Sometimes, the joints can pop or crack as a person stretches or moves. A muscle spasm, an injury, costochondritis, and surgery are ...

Researchers working in New South Wales, Australia, at a fossil site called the McGraths Flat discovered the bones of an ancient fish species, according to a study published March 17 in the ...