(1) Rugae. The mucous membrane in the roof of the mouth forms ridges (or
corrugations) called rugae. Rugae are elevated folds or wrinkles of fibrous soft tissue
situated in the hard palate, just behind the maxillary anterior teeth. The rugae aid in the
formation of speech sounds and also serve as secondary stress-bearing areas for
(2) Maxillary tuberosity. The maxillary alveolar ridge ends in a rounded
prominence distal to the last tooth on each side. This prominence is called the maxillary
tuberosity. It plays a part in the retention and stability of maxillary dentures.
(3) Hamular notch. Just distal to the maxillary tuberosity, in the posterior
palate where the maxilla and sphenoid bone unite, is a notch called the hamular notch.
The posterior border of a full upper denture is usually designed to fit into this area.
(4) Uvula. Hanging from the middle or highest point of the soft palate is the
uvula (a fleshy and somewhat cone-shaped mass of tissue). See figure 3-1. The uvula
plays a part in swallowing; in combination with certain muscles of the neck, it closes the
passage between the nasal cavity and the throat. In this way, food is kept from entering
the nasal cavity and, at the same time, air is prevented from being swallowed. The
uvula also assists in speaking. It vibrates and gives resonance to the voice.
(5) Tonsils. On the concave walls of the soft palate are small masses of
tissue. These are the tonsils. When inflamed, they are enlarged and reddened, a
condition called tonsillitis.
b. Floor of the Mouth. The floor of the mouth is formed by the mylohyoid
(1) Lingual frenum. By pulling the tip of the tongue up and back, one can
see a fold of tissue which connects the under surface of the tongue with the floor of the
mouth. This is called the lingual frenum.
(2) Openings of submandibular salivary glands. These openings are on the
floor of the mouth toward the anterior extremity of the lingual frenum. Two slight
elevations can be seen, one on each side of the lingual frenum.
(3) Openings of sublingual salivary glands. These glands lie directly
beneath the anterior part of the floor of the mouth. They open directly onto the floor of
the mouth through many tiny indistinct openings.
c. Tongue. The tongue occupies most of the space within the mouth when it is
closed. The tip of the tongue (the thin anterior part) is freely movable. The body is
connected to the sides of the mandible and is also movable, but to a more limited
extent. The posterior part has a broad muscular attachment both to the hyoid bone and
to the mandible. The tongue is the principal organ for the sense of taste and the
production of speech. It aids in masticating (chewing, grinding) and swallowing food.