Definition of "periosteum" [per•i•os•te•um]

• The dense fibrous membrane covering the surface of bones except at the joints and serving as an attachment for muscles and tendons. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The shaft is covered by a membrane called the periosteum and is what the muscles attach to."
• "The treatment for injuries to the periosteum is the same as that recommended for splints."
• "The mildest degree consists in a bruising of the periosteum, which is raised from the bone by an effusion of blood, constituting a _hæmatoma of the periosteum_."