Louie Al-Faraje - Clinical Anatomy for Oral Implantology

The anatomy of the pterygopalatine fossa is especially important for the following surgeries:

Vidian neurectomy (the surgical sectioning of the pterygoid nerve for the treatment of vasomotor rhinitis, Sluder’s neuralgia of the pterygopalatine ganglion, crocodile tears syndrome, allergic rhinitis [hay fever], and nasal polyposis)

Transmaxillary ligature of the maxillary artery (in cases of severe nasal bleeding that cannot be controlled by anterior and/or posterior tamponades)

Craniofacial surgery

Surgery of the base of the skull or nasopharynx

Lateral approaches to the orbit

Traumatology

Vasomotor rhinitis is a condition that results from a relative imbalance of parasympathetic to sympathetic stimulation of the blood vessels and glands of the nasal mucosa. It is characterized by symptoms of clear rhinorrhea and nasal congestion.

Sluder’s neuralgia of the pterygopalatine ganglion is a rare disorder characterized by unilateral, severe, burning, boring, or nagging headache, starting around the eye and the bridge of the nose and radiating to the maxilla and maxillary teeth, zygoma, mastoidal area and occiput, or even as far down as the shoulder and arm.

Crocodile tears syndrome (gustatory lacrimation; tearing on eating) is a rare complication of a facial nerve lesion proximal to the geniculate ganglion, whereby regenerating preganglionic salivary fibers intended for the chorda tympani nerve are misdirected to the sphenopalatine ganglion, which project to the lacrimal gland.

The principal veins of the head and neck are the internal jugular vein, the external jugular vein, and the anterior jugular vein. The internal jugular vein collects blood from the interior of the skull, the anterior and lateral face, and the oral cavity and the neck via the sigmoid sinus, the inferior petrosal sinuses, and the facial, lingual, superior, and middle thyroid and retromandibular (anterior division) veins. The external jugular vein collects blood from the lateral skull and the occiput via the posterior auricular and the retromandibular (posterior division) veins. The anterior jugular vein collects blood from the anterior neck region.

The pterygoid venous plexus is situated on the medial side of the mandibular ramus within the pterygoid muscles. It is linked to the facial vein via the deep facial vein, to the retromandibular vein via the maxillary vein, and to the cavernous sinus via the sphenoidal emissary vein. The pterygoid plexus drains into the jugular veins.

This plexus is of a special importance to dentists because if the needle is overinserted during posterosuperior alveolar block, it may penetrate the pterygoid plexus of the vein and the maxillary artery in the infratemporal fossa (Fig 1-9), thus causing hematoma. This results in extraoral swelling a few minutes after the injection. The hematoma will cause tissue tenderness and discoloration, which will last until the blood is broken down by the body, and possible spread of infection to the cavernous venous sinus if the needle is contaminated. A hematoma can also result during other blocks, such as infraorbital and inferior alveolar blocks. To avoid injection into blood vessels, aspiration should always be attempted for all injections.

FIG 1-9 Pterygoid venous plexus.

The 12 cranial nerves control motor and sensory functions of the head and neck. Figure 1-10 and Table 1-2summarize the skull base foramina from which these nerves exit the skull and their functions.

FIG 1-10 The origin of the cranial nerves as seen from an inferior aspect of the brain. n.—nerve.

TABLE 1-2 Exit foramina and functions of the cranial nerves

The maxillary nerve (Fig 1-11a) is the second branch of the fifth cranial nerve (trigeminal nerve). Its function is the transmission of sensory fibers from the maxillary teeth, the nasal cavity, the sinuses, and the skin between the palpebral fissure and the mouth (Figs 1-11b and 1-11c). In the cranium, the maxillary nerve branches off into the middle meningeal nerve, then passes through the foramen rotundum into the pterygopalatine fossa, where it divides into the zygomatic nerve, the ganglionic branches (pterygopalatine branches), and the infraorbital nerve.