The mandible is a U-shaped bone. It is the only mobile bone of the facial skeleton, and, since it houses the lower teeth, its motion is essential for mastication. It is formed by intramembranous ossification. The mandible is composed of 2 hemimandibles joined at the midline by a vertical symphysis.
1 For example, AT&T charges $23 for a home residential line that includes a few additional basic features such as caller ID, call waiting and voicemail. 2  Home phone service plans that include local and long-distance calling cost $30-$45 per month.
Note the ATT Customer Service Number, or look for a specific one here. Main ATT phone number: 1-800-331-0500 or 611 from your wireless phone. ATT Customer Service Hours: