- a large, bony prominence on the base of the skull behind the ear, containing air spaces that connect with the middle ear cavity.
Origin of mastoid process
First recorded in 1725–35
Also called mastoid, mastoid bone.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- A conical protuberance of the posterior portion of the temporal bone that is situated behind the ear and serves as a site of muscle attachment.mastoid bone
- The part of the first pharyngeal arch in the embryo, developing into the upper jaw in the embryo.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- A protruding bony area in the lower part of the skull that is located behind the ear in humans and many other vertebrates and serves as a site of muscle attachment. The mastoid process contains small air-filled cavities called mastoid cells that communicate with the middle ear.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.