ABSTRACT
The maxillae (Illustration C, 1) and mandible (Illustration D, 2) support the oral cavity, for drinking, eating, chewing and speech. The oral cavity lies between the cheeks and lips, which are formed by skin and mucous membrane with muscle between. The oral cavity proper is internal to the teeth. The vestibule is outside the teeth and compressed by buccinator and orbicularis oris. Posteriorly, the cavity is continuous with the oropharynx (3). The hard (4) and soft (5) palates form the roof. The floor comprises mylohyoid muscle (6), which arises from the inner aspect of the mandible to fuse with its neighbour in the midline, forming a central raphe from mandible to hyoid (7). Further support and control of the floor of the mouth, and therefore the tongue, is provided by geniohyoid (8), internal to mylohyoid, and by the anterior belly of digastric external to it.
