Facial  (Labial) - toward the lips; that surface of anterior teeth directly contacting or facing the lips/ cheek.

Lingual - toward the tongue; that surface of anterior and posterior teeth  immediately adjacent to or facing the tongue.

The mental ridges are elevated ridges of bone located along the anterior aspect of the mandible. The ridges are also known as the mental tubercles and fuse at the midline to form the mental protuberance, in the anterior most aspect of the mandible. This periapical radiograph demonstrates the radiopaque margin of the mental ridges and mental fossa in between the ridges.

The genial tubercles are small bony spines found on the lingual aspect of the mandible adjacent to the midline at the attachment of the geniohyoid and genioglossus muscles.

The small opening right in the middle of the tubercles is called the lingual foramen, an opening in the lingual midline of the mandible for a small vessel.