Pterygopalatine (sphenopalatine) ganglion
Ganglion · CN VII Greater petrosal Pterygopalatine fossa
Suspended from the maxillary nerve in the pterygopalatine fossa. The greater petrosal nerve (VII) joins the deep petrosal nerve (sympathetic) to form the nerve of the pterygoid canal, which enters the ganglion; only the parasympathetic fibres synapse. It is the secretomotor relay for the lacrimal, nasal, palatine and pharyngeal glands.
Traced from the start
- Parasympathetic (craniosacral) outflow
- Superior and inferior salivatory nuclei (CN VII and IX)
- Pterygopalatine (sphenopalatine) ganglion
Detail
- Preganglionic route
- Superior salivatory nucleus → nervus intermedius → geniculate ganglion → greater petrosal nerve → foramen lacerum → nerve of pterygoid canal (Vidian)
- Sympathetic passers-by
- Deep petrosal nerve fibres from the internal carotid plexus pass through to nasal mucosa vessels — vasoconstrictors, hence sympathomimetic decongestants
- Postganglionic distribution
- Lacrimal gland via zygomatic nerve; nasal, palatine and pharyngeal glands via the ganglion's own branches (nasopalatine, greater and lesser palatine)
When it goes wrong
Aberrant regeneration after facial nerve palsy directs salivary fibres into the greater petrosal nerve
Crocodile tears (gustatory lacrimation): profuse ipsilateral tearing while eating
Cluster headache activates the trigeminal–autonomic reflex through this ganglion
Ipsilateral lacrimation, nasal congestion and rhinorrhoea accompany the periorbital pain, often with a partial Horner syndrome
Practise this structure
2 questions in the bank tagged Facial Nerve.
A 52-year-old woman has had two months of numbness over the right forehead, the right upper eyelid and the tip of her nose, with a gritty feeling in the right e…
Foundations · middle twist
A 44-year-old man has had drooping of the right side of his face for three days. He drools from the right corner of his mouth, the right nasolabial fold is flat…
Foundations · common