Corpus: Pterygopalatine ganglion

The pterygopalatine ganglion is a parasympathetic ganglion located in the pterygopalatine fossa at the base of the skull. It is one of the key parasympathetic head ganglia.

2.1. Topography

The pterygopalatine ganglion is closely associated with several anatomical structures, including:

• the foramen sphenopalatinum
• the maxillary artery
• the maxillary nerve

2.2. Fibres

The pterygopalatine ganglion is traversed by sensory, sympathetic, and parasympathetic fibers. However, only the parasympathetic fibers synapse within the ganglion; the sensory and sympathetic fibers simply pass through it.

2.2.1. Parasympathetic fibres

The parasympathetic fibers originate from the nerve cells of the superior salivatory nucleus. These fibers branch from the facial nerve (cranial nerve VII) at the geniculate ganglion and travel with the greater petrosal nerve and the nerve of the pterygoid canal to reach the pterygopalatine ganglion. Here, they synapse with postganglionic neurons. The postganglionic fibers then travel primarily via branches of the maxillary nerve to reach their target organs, including:

• Rami orbitales: To the mucous membranes of the ethmoid cells and the sphenoid sinus.
• Rami nasales: To the nasal mucosa in the posterior section of the nasal cavity.
• Pharyngeal ramus: To the mucous membrane of the nasopharynx.
• Nasopalatine nerve: To the mucous membrane of the anterior palate.
• Greater palatine nerve: To the palatal and nasal mucosa.
• Nervi palatini minores: To the soft palate.
• Zygomatic and lacrimal nerves: To the lacrimal gland.

2.2.2. Sympathetic fibres

The sympathetic fibers in the pterygopalatine ganglion are postganglionic, originating from the superior cervical ganglion. They reach the ganglion via the internal carotid plexus, the deep petrosal nerve, and the nerve of the pterygoid canal. These fibers pass through the ganglion without synapsing and travel to the lacrimal gland.

2.2.3. Sensitive fibres

Sensory fibers from the maxillary nerve enter the ganglion via the rami ganglionares. These fibers also pass through the ganglion without synapsing and carry afferent signals from the nasal, palatal, and pharyngeal mucosa.

A pterygopalatine ganglion blockade is a treatment method used for cluster headaches and certain forms of migraine. This procedure involves infiltrating the tissue around the ganglion with a local anesthetic to alleviate pain.