Читать книгу Feline Dentistry - Jan Bellows - Страница 19

Sensory input is received from maxillary and mandibular divisions of the trigeminal nerve. The maxillary branch leaves the trigeminal ganglion, then exits the cranial cavity through the foramen rotundum, courses through the alar canal and the pterygopalatine fossa to enter the infraorbital canal. Just before entering the caudal limit of the infraorbital canal, the nerve branches into the major and minor palatine nerves. These nerves innervate the hard and soft palates and the nasopharynx. The palatine nerves are desensitized by the maxillary nerve block.

Figure 1.3 Caudal oral cavity.

The maxillary branch of the trigeminal nerve also branches out into the caudal maxillary alveolar nerve, which innervates the maxillary first molar, the buccal gingiva, and mucosa. This area is blocked by the infraorbital nerve block.

After giving off the caudal maxillary alveolar nerve, the maxillary nerve enters the infraorbital canal, where it is called the infraorbital nerve. While the infraorbital nerve is traversing the infraorbital canal, it gives off two more branches that exit ventrally from the canal. The middle maxillary alveolar nerve innervates the premolars and associated buccal gingiva. The rostral maxillary alveolar nerve supplies the canines, incisors, and associated buccal gingiva. The remaining fibers of the infraorbital nerve then exit the rostral extent of the infraorbital canal to innervate the lateral and dorsal cutaneous structures of the rostral maxilla and upper lip. The middle maxillary alveolar, rostral maxillary alveolar, and the infraorbital nerves are anesthetized by the rostral infraorbital nerve block.

The mandibular division of the trigeminal nerve arises from the trigeminal ganglion, exits the cranium via the foramen ovale, and divides into multiple branches. The divisions include the sensory buccal nerves, lingual nerve, and mandibular (inferior alveolar) nerve. The buccal nerves receive stimuli from the facial musculature, skin and mucosa of the cheek, and buccal gingiva along the caudal mandible.

The hypoglossal nerve innervates the tongue, the floor of the mouth, the lingual gingiva, and the mandibular salivary gland. The mandibular nerve enters the mandible on the lingual side, via the mandibular foramen. The nerve then courses rostrally within the mandibular canal to innervate the mandibular teeth to the midline. This nerve can be blocked by the mandibular (inferior alveolar) nerve block. Rostral to the third premolar tooth, the mandibular nerve gives off mental nerve branches. These branches exit through the mental foramina (rostral, middle, and caudal) and innervate the cutaneous areas of the chin and lip, and the rostral buccal gingiva and mucosa. These nerves are blocked by use of mental nerve blocks (usually the middle mental foramen is used).