The pterygopalatine ganglion (of Meckel), the largest of the parasympathetic ganglia associated with the branches of the Maxillary Nerve (branch of trigeminal nerve), is deeply placed in thepterygopalatine fossa, close to the sphenopalatine foramen. It is triangular or heart-shaped, of a reddish-gray color, and is situated just below the maxillary nerve as it crosses the fossa.
The pterygopalatine ganglion supplies the lacrimal gland (tear ducts), paranasal sinuses, glands of the mucosa of the nasal cavity and pharynx, the gingiva, and the mucous membrane and glands of the hard palate. It communicates anteriorly with the nasopalatine nerve.
According to Wikipedia (below) there are sensory, sympathetic and parasympatheic roots
Its sensory root is derived from two sphenopalatine branches of the maxillary nerve; their fibers, for the most part, pass directly into the palatine nerves; a few, however, enter the ganglion, constituting its sensory root.
Parasympathetic root
Its parasympathetic root is derived from the nervus intermedius (a part of the facial nerve) through the greater petrosal nerve.
In the pterygopalatine ganglion, the preganglionic parasympathetic fibers from the greater petrosal branch of the facial nerve synapse with neurons whose postganglionic axons, vasodilator, and secretory fibers are distributed with the deep branches of the trigeminal nerve to the mucous membrane of the nose, soft palate, tonsils, uvula, roof of the mouth, upper lip and gums, and upper part of the pharynx. It also sends postganglionic parasympathetic fibers to the lacrimal nerve (a branch of the Ophthalmic nerve, also part of the trigeminal nerve) via the zygomatic nerve, a branch of the maxillary nerve (from the trigeminal nerve), which then arrives at the lacrimal gland.
The nasal glands are innervated with secretomotor from the nasopalatine and greater palatine nerve. Likewise, the palatine glands are innervated by the nasopalatine, greater palatine nerve and lesser palatine nerves. The pharyngeal nerve innervates pharyngeal glands. These are all branches of maxillary nerve.
Sympathetic root
The ganglion also consists of sympathetic efferent (postganglionic) fibers from the superior cervical ganglion. These fibers, from the superior cervical ganglion, travel through the carotid plexus, and then through the deep petrosal nerve. The deep petrosal nerve joins with the greater petrosal nerve to form the nerve of the pterygoid canal, which enters the ganglion.
TRIGEMINAL AUTONOMIC CEPHALGIAS
Some primary headaches are characterized by severe pain in or around the eye on one side of the face and autonomic(or involuntary) features on the same side, such as red and teary eye, drooping eyelid, and runny nose. These disorders, called trigeminal autonomic cephalgias (cephalgia meaning head pain), differ in attack duration and frequency, and have episodic and chronic forms. Episodic attacks occur on a daily or near-daily basis for weeks or months with pain-free remissions. Chronic attacks occur on a daily or near-daily basis for a year or more with only brief remissions.
Cluster headache - the most severe form of primary headache-involves sudden, extremely painful headaches that occur in "clusters," usually at the same time of the day and night for several weeks. They strike one side of the head, often behind or around one eye, and may be preceded by a migraine-like aura and nausea. The pain usually peaks 5 to 10 minutes after onset and continues at that intensity for up to 3 hours. The nose and the eye on the affected side of the face may get red, swollen, and teary. Some people will experience restlessness and agitation, changes in heart rate and blood pressure, and sensitivity to light, sound, or smell. Cluster headaches often wake people from sleep.
Cluster headaches generally begin between the ages of 20 and 50 but may start at any age, occur more often in men than in women, and are more common in smokers than in nonsmokers. The attacks are usually less frequent and shorter than migraines. It's common to have 1 to 3 cluster headaches a day with 2 cluster periods a year, separated by months of freedom from symptoms. The cluster periods often appear seasonally, usually in the spring and fall, and may be mistaken for allergies. A small group of people develop a chronic form of the disorder, which is characterized by bouts of headaches that can go on for years with only brief periods (1 month or less) of remission. Cluster headaches occur more often at night than during the day, suggesting they could be caused by irregularities in the body's sleep-wake cycle. Alcohol (especially red wine) and smoking can provoke attacks. Studies show a connection between cluster headache and prior head trauma. An increased familial risk of these headaches suggests that there may be a genetic cause.
Treatment options include oxygen therapy-in which pure oxygen is breathed through a mask to reduce blood flow to the brain-and triptan drugs. Certain antipsychotic drugs, calcium-channel blockers, and anticonvulsants can reduce pain severity and frequency of attacks. In extreme cases, electrical stimulation of the occipital nerve to prevent nerve signaling or surgical procedures that destroy or cut certain facial nerves may provide relief.
Paroxysmal hemicrania is a rare form of primary headache that usually begins in adulthood. Pain and related symptoms may be similar to those felt in cluster headaches, but with shorter duration. Attacks typically occur 5 to 40 times per day, with each attack lasting 2 to 45 minutes. Severe throbbing, claw-like, or piercing pain is felt on one side of the face-in, around, or behind the eye and occasionally reaching to the back of the neck. Other symptoms may include red and watery eyes, a drooping or swollen eyelid on the affected side of the face, and nasal congestion. Individuals may also feel dull pain, soreness, or tenderness between attacks or increased sensitivity to light on the affected side of the face. Paroxysmal hemicrania has two forms: chronic, in which individuals experience attacks on a daily basis for a year or more, and episodic, in which the headaches may stop for months or years before recurring. Certain movements of the head or neck, external pressure to the neck, and alcohol use may trigger these headaches. Attacks occur more often in women than in men and have no familial pattern.
The nonsteroidal anti-inflammatory drug indomethacin can quickly halt the pain and related symptoms of paroxysmal hemicrania, but symptoms recur once the drug treatment is stopped. Non-prescription analgesics and calcium-channel blockers can ease discomfort, particularly if taken when symptoms first appear.
SUNCT (Short-lasting, Unilateral, Neuralgiform headache attacks with Conjunctival injection and Tearing) is a very rare type of headache with bursts of moderate to severe burning, piercing, or throbbing pain that is usually felt in the forehead, eye, or temple on one side of the head. The pain usually peaks within seconds of onset and may follow a pattern of increasing and decreasing intensity. Attacks typically occur during the day and last from 5 seconds to 4 minutes per episode. Individuals generally have five to six attacks per hour and are pain-free between attacks. This primary headache is slightly more common in men than in women, with onset usually after age 50. SUNCT may be episodic, occurring once or twice annually with headaches that remit and recur, or chronic, lasting more than 1year.
Symptoms include reddish or bloodshot eyes (conjunctival injection), watery eyes, stuffy or runny nose, sweaty forehead, puffy eyelids, increased pressure within the eye on the affected side of the head, and increased blood pressure.
SUNCT is very difficult to treat. Anticonvulsants may relieve some of the symptoms, while anesthetics and corticosteroid drugs can treat some of the severe pain felt during these headaches. Surgery and glycerol injections to block nerve signaling along the trigeminal nerve have poor outcomes and provide only temporary relief in severe cases. Doctors are beginning to use deep brain stimulation (involving a surgically implanted battery-powered electrode that emits pulses of energy to surrounding brain tissue) to reduce the frequency of attacks in severely affected individuals.
Oomen KP, van Wijck AJ, Hordijk GJ, de Ru JA.
Department of Otolaryngology, Central Military Hospital, Utrecht, The Netherlands.
Oomen KPQ, van Wijck AJM, Hordijk GJ & de Ru JA. Sluder's neuralgia: a trigeminal autonomic cephalalgia?
PMID: 19614698 [PubMed - as supplied by publisher]