Pterygopalatine ganglion

Topography and adjacent structures

The ganglion is located in the pterygopalatine fossa (fossa pterygopalatina). This fossa has openings through which nerves and vessels pass, topographically and functionally related to the ganglion:

• Foramen rotundum (foramen rotundum) — transmits the maxillary nerve (n. maxillaris) into the fossa.
• Pterygoid canal (canalis pterygoideus) — transmits the nerve and artery of the same name to the ganglion.
• Greater palatine canal (canalis palatinus major) — transmits the greater palatine nerve (n. palatinus major).
• Sphenopalatine foramen (foramen sphenopalatinum) — transmits the posterior nasal branches.

Roots of the ganglion (sources of innervation)

The pterygopalatine ganglion is formed by three types of nerve fibers:

• Parasympathetic root — greater petrosal nerve (n. petrosus major). It originates from the nervus intermedius (n. intermedius, part of the facial nerve — CN VII). The fibers synapse in the pterygopalatine ganglion.
• Sympathetic root — deep petrosal nerve (n. petrosus profundus).
• Sensory root — ganglionic branches (nn. pterygopalatini) arising from the maxillary nerve.

Formation of the Vidian nerve: The greater and deep petrosal nerves join to form the nerve of the pterygoid canal (n. canalis pterygoidei). It passes through the canal of the same name at the base of the pterygoid process and enters the ganglion.

Branches and zones of innervation

Postganglionic and transit fibers of the ganglion are associated with several head structures:

• Lacrimal gland: receives efferent parasympathetic secretory fibers. The source of impulses is the superior salivatory nucleus (nucleus salivatorius superior).
• Mucous membrane of the nasal cavity: the posterior parts are innervated by the posterior nasal branches (nn. nasales posteriores).
• Palate and nasopharynx.

The ganglion gives rise to the following nerves: greater, middle, and lesser palatine nerves (n. palatinus major, medius et anterior), as well as the nasopalatine nerve (n. nasopalatinus).

Note: Diagrams of taste pathways indicate a possible alternative pathway for afferent fibers from the anterior part of the tongue via the greater petrosal nerve and pterygopalatine ganglion.

Regulation of lacrimation

Since the ganglion is involved in the innervation of the lacrimal gland, various reflexes are mediated through it:

• Emotional lacrimation: hypothalamic central influence (emotions) on the lacrimal glands is mediated via the brainstem reticular formation.
• Reflex lacrimation upon conjunctival irritation: mediated by fibers running from the spinal trigeminal nucleus (nucleus spinalis nervi trigemini) to the lacrimal glands.

Blood supply

Blood supply to the pterygopalatine ganglion and adjacent tissues is provided by the artery of the pterygoid canal (a. canalis pterygoidei). It passes through the canal of the same name into the pterygopalatine fossa.

Class and exam questions

What else to study on this topic

• Pterygopalatine fossa (Fossa pterygopalatina)
• Maxillary nerve (Nervus maxillaris)
• Facial nerve (Nervus facialis)
• Autonomic Nervous System

Other topics in the "Anatomical Structures" section

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