The Mastoid Jaw Bone, or the Jawbone Bone called os fonticuli, is located between the first molar located above and the temporal bone. Its size is 2.5-3 cm, it consists of two parts. The lower part is more voluminous and massive. The parts connect vessels, nerves and fibrous connections, which have a rather different structure, due to which the jaws take their stable position.
The upper part of the bone is located in the auditory fossa, and has mobility, as it is capable of moving the temporal bone in the maxillary bone, almost halfway down. And for the convenience of auditory perception and sound production, in order to keep the auditory ossicles in place during a conversation, the special smooth surface of the bone is covered with a layer of the finest pile. This bone thereby ensures the mobility of the auditory ossicles, which facilitates their better passage of sound waves through the auditory tube, and also makes the jaw mobile (due to this, the bone is called the “bone of the anastomosis”). Due to its size, the bone is able to separate muscle pressure and tension of the upper jaw, thereby serving as a shock absorber. In the auditory region there are arched bone formations, and its edges have thin layers of cartilaginous tissue.