The pterygopalatine ganglion is a collection of cells located in the pterygopalatine fossa. It is identified as one of the four parasympathetic ganglia, which can be found in the head and neck. The pterygopalatine ganglion is also referred to as Meckel's ganglion, named after 18th-century German anatomist Johann Friedrich Meckel the Elder. It also is called the ganglion pterygopalatinum, nasal ganglion or sphenopalatine ganglion. It has three roots, which are called the sensory, motor, and sympathetic roots.
Ganglion is the clinical term given to the gray-matter mass made up of nerve cells, which are located outside the central nervous system (CNS). This part of the nervous system is so named because it combines information retrieved from all parts of the body, thereby coordinating the body's functions. As the major part of the nervous system, the CNS contains its prime components: the brain and spinal cord.
The parasympathetic ganglia, the category to which the pterygopalatine ganglion belongs, is part of the peripheral nervous system (PNS). This is the subdivision of the nervous system that houses ganglia, among other types of nerves. It is responsible for connecting the CNS with the organs and limbs for innervation. These parts of the body would lack stimulation without such a supply.
Of triangular or heart-like shape with a reddish-gray pigmentation, the parasympathetic ganglion is named after its location, the pterygopalatine fossa. This is a teardrop-shaped channel found at the skull's lateral side, immediately behind the upper jaw, or maxilla. It serves as the primary site for blood supply and innervation of the upper jaw with the maxillary artery and maxillary nerve.
As for the pterygopalatine ganglion itself, it is right below the maxillary nerve and is responsible for innervating specific sites of the head and neck. This includes the lachrymal glands, which are almond-shaped glands located at the eyes; the paranasal sinuses, which are air-filled spaces located around the nasal cavity; and the gingiva, or the gums. Also, the pterygopalatine ganglion works with the nasopalatine nerve, or sphenopalatine nerve, which innervates the front teeth of the maxilla.
The pterygopalatine ganglion is the biggest of the parasympathetic ganglia, the others being the ciliary ganglion, otic ganglion and submandibular ganglion. The ciliary ganglion is located behind the orbits, which are the cranial sockets that house the eyes and their appendages. The otic ganglion is located in a hole at the base of the skull called the foramen ovale. The submandibular ganglion is mainly named after its site of location, which is the lower jaw, or mandible. It is responsible for innervating the oral salivary glands called the submandibular gland and sublingual gland.