The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) component of the glossopharyngeal nerve The glossopharyngeal nerve, known as the ninth cranial nerve, is a mixed nerve that carries afferent sensory and efferent motor information. It exits the brainstem out from the sides of the upper medulla, just rostral to the vagus nerve. The motor division of the glossopharyngeal nerve is derived from the basal plate of the embryonic medulla oblongata, while the sensory division originates f…Glossopharyngeal nerve
What is the function of lesser petrosal nerve?
The lesser petrosal nerve is a root of the otic ganglion. Its fibers are derived from the facial and glossopharyngeal nerve via tympanic plexus. Postsynaptic fibres leaving otic ganglion join auriculotemporal nerve and inervate the parotid gland .
What passes through the hiatus for the lesser petrosal nerve?
After arising in the tympanic plexus, the lesser petrosal nerve passes forward and then through the hiatus for lesser petrosal nerve on the anterior surface of the petrous part of the temporal bone into the middle cranial fossa.
Where does the lesser petrosal nerve connect to the chorda tympani?
The lesser petrosal nerve also forms a connection between the otic ganglion (where it terminates), the facial nerve and the glossopharyngeal nerve. This nerve is slender and makes its way in the middle ear to meet the stapedius muscle. The chorda tympani nerve arises from the facial nerve a few millimeters above the stylomastoid foramen.
Where does the greater petrosal nerve exit the temporal bone?
Formerly known as the greater superficial petrosal nerve, the greater petrosal nerve exits the temporal bone by the Fallopian hiatus and runs through an osseous conduit, which brings it to the foramen lacerum. At the anterior face of the petrous pyramid it receives sensory fibers from the glossopharyngeal nerve.
Where does the lesser petrosal nerve arise?
the tympanic plexusAfter arising in the tympanic plexus, the lesser petrosal nerve passes forward and then through the hiatus for lesser petrosal nerve on the anterior surface of the petrous part of the temporal bone into the middle cranial fossa.
Where does the deep petrosal nerve come from?
The deep petrosal nerve is a branch from the internal carotid plexus. The plexus is located on the lateral side of the internal carotid as it courses superiorly. The deep petrosal enters the skull through the carotid canal with the internal carotid artery.
What does the Greater and lesser petrosal nerve innervate?
They travel together from the ganglion to the mouth. There, the greater palatine nerve innervates the mucous membrane of the rear portion of the hard palate. The lesser palatine nerves innervate the soft palate. They both contribute to your sense of taste.
Is lesser petrosal nerve a branch of Glossopharyngeal?
The lesser petrosal nerve carries preganglionic parasympathetic fibers to the parotid gland. It is considered a branch of the glossopharyngeal nerve although it receives contributions from two further sources 3: tympanic plexus: glossopharyngeal nerve via Jacobson's nerve (main contribution)
What does the petrosal nerve innervate?
The greater petrosal nerve (or greater superficial petrosal nerve) is a nerve in the skull that branches from the facial nerve; it forms part of a chain of nerves that innervate the lacrimal gland. The preganglionic parasympathetic axons of this nerve synapse in the pterygopalatine ganglion.
What nerve passes through pterygoid canal?
The vidian nerveThe vidian nerve is formed by the confluence of the greater superficial petrosal and deep petrosal nerves and travels in the pterygoid canal carrying the parasympathetic fibers, which synapse in the pterygopalatine ganglion, and the postganglionic fibers are distributed with the branches of the maxillary nerve.
How many Petrosal nerves are there?
Six petrosal nerves have been described: exter- nal, deep, small deep, smallest deep, greater, and lesser. One of these is a branch of the facial nerve, one is a branch of the glossopharyngeal nerve, and four are derived from sympathetic fibers.
Is the greater petrosal nerve a branch of the facial nerve?
Excerpt. The greater petrosal nerve or superficial petrosal nerve is a branch of the nervus intermedius (nerve of Wrisberg) that carries parasympathetic, taste, and sensory fibers of the facial cranial nerve (CN VII).
What nerve is responsible for gag reflex?
The afferent limb of the reflex is supplied by the glossopharyngeal nerve (cranial nerve IX), which inputs to the nucleus solitarius and the spinal trigeminal nucleus. The efferent limb is supplied by the vagus nerve (cranial nerve X) from the nucleus ambiguus. All of these are located in the medulla.
Why vagus and glossopharyngeal nerves are connected to each other?
The glossopharyngeal and vagus cranial nerves provide the brainstem with sensory inputs from different receptors in the heart, lung, and vasculature. This afferent information is critical for the short-term regulation of arterial blood pressure and the buffering of emotional and physical stressors.
Where does the glossopharyngeal nerve originate?
medulla oblongataThe glossopharyngeal nerve is the 9th cranial nerve (CN IX). It is one of the four cranial nerves that has sensory, motor, and parasympathetic functions. It originates from the medulla oblongata and terminates in the pharynx.
Is deep petrosal nerve in middle cranial fossa?
Leaving the geniculate ganglion, the greater petrosal nerve pierces the upper surface of petrous temporal bone, enters the middle cranial fossa, is joined at foramen lacerum by the deep petrosal nerve (sympathetic fibres from internal carotid plexus) to form the nerve of the pterygoid canal, which goes to the ...
What passes through the Vidian Canal?
The vidian canal (VC), a bony tunnel in which the vidian artery and nerve pass, has been widely known as an important landmark to identify the anterior genu of the petrous carotid artery (AGPCA) especially during lateral extended endoscopic endonasal approachs (LEEEAs).
Where does internal carotid plexus come from?
One large branch (the internal carotid nerve) leaves the ganglion and branches to form the internal carotid plexus, which travels on the internal carotid artery into the cranial cavity.
What runs through foramen lacerum?
The two nerves that pass from the foramen lacerum are the greater petrosal nerve, which represents the pre-ganglionic parasympathetic fibers, and the deep petrosal nerve which, representing the post-ganglionic sympathetic fibers.
What is the lesser petrosal nerve?
The lesser petrosal nerve (Figure 26.3) is a continuation of the presynaptic fibers of the tympanic branch of the glossopharyngeal nerve with contributions from the nervus intermedius part of the facial nerve, and the auricular branch (Alderman’s or Arn old’s nerve) of the va gus nerve. This communicating branch carries small myelinated fibers with some of these being autonomic in nature. The lesser petrosal nerve receives a communicating branch composed of fibers from the nervus intermedius and Arnold’s nerve from either the facial nerve at the geniculate ganglion (geniculotympanic nerve) or distal to the geniculate ganglion or from the greater petrosal nerve. Ganglion cells may be found along the lesser petrosal nerve.
Which nerve is the communicating branch of the petrosal nerve?
The lesser petrosal nerve receives a communicating branch composed of fibers from the nervus intermedius and Arnold’s nerve from either the facial nerve at the geniculate ganglion (geniculotympanic nerve) or distal to ...
What nerves do otic ganglions use?
The otic ganglion receives preganglionic axons from the glossopharyngeal nerve via the tympanic plexus and lesser petrosal nerve; however, lesion studies suggest an additional preganglionic pathway from the facial nerve via the chorda tympani. Postganglionic axons leave the ganglion mostly via the auriculotemporal nerve to reach the parotid gland; some neurons may project to the vessels of the jaw and cerebral circulation. Like neurons of the pterygopalatine and submandibular ganglia, otic ganglion neurons utilize ACh, VIP, and NO. There are several microganglia in association with the salivary glands, in several distal branches of the facial and glossopharyngeal nerves, and in the cavernous plexus. The facial and glossopharyngeal nerves communicate with the cavernous plexus via the greater superficial petrosal and lesser petrosal nerves, respectively; ganglion cells along these pathways contain VIP and may contribute to vasodilator innervation of the cerebral circulation.
How to assess glossopharyngeal nerve?
When assessing the glossopharyngeal nerve, the first thing to do is simply listening to the patient talking. Any abnormality of the voice, for example, hoarse, whispering, or a nasal voice may give a clue as to an abnormality. Also, ask the patient if they have any difficulty in swallowing. The result of a glossopharyngeal nerve (and related cranial nerves, eg, vagus and accessory nerves due to their close proximity to each other) may be dysphagia (difficulty swallowing), aspiration pneumonia, or dysarthria (difficulty in the motor control of speech).
Where are the secretomotor axons located?
The secretomotor axons of the glossopharyngeal nerve originate in preganglionic neurons located in the salivatory nucleus in the upper medulla and lower pons. These axons follow the tympanic and lesser petrosal nerves and innervate the otic ganglion, located just medial to the mandibular branch of the trigeminal nerve.
Which ganglia are found at the point of entry to the jugular foramen?
At the point of entry to the jugular foramen, two ganglia are found—an inferior ganglion and a superior ganglion. Both of these ganglia contain the cell bodies of the afferent fibers contained within the glossopharyngeal nerve.
Which nerve contains sensory fibers?
The glossopharyngeal nerve contains sensory fibers from the pharynx, tongue (posterior one-third), and the tonsils. It also contains secretomotor fibers destined for the parotid gland as well as motor fibers for the stylopharyngeus. Finally, it also contains taste fibers, from the posterior one-third of the tongue. Therefore, the glossopharyngeal nerve is a rather complex and important nerve supplying a variety of structures.
Which nerve carries parasympathetic fibers to the parotid gland?
The lesser petrosal nerve carries preganglionic parasympathetic fibers to the parotid gland. It is considered a branch of the glossopharyngeal nerve although it receives contributions from two further sources 3: The nerve passes through its own canal to the floor of the middle cranial fossa, where it is located between the two layers ...
Where is the nervus intermedius located?
auricular branch (Arnold’s nerve) of the vagus nerve. The nerve passes through its own canal to the floor of the middle cranial fossa, where it is located between the two layers of the dura mater between the petrous branch of the middle meningeal artery (medial) and the superior tympanic artery (lateral) 3 . ...
Why is it important to know about the greater petrosal nerve?
The greater petrosal nerve has some known variations: 1 . Its distance from certain bony structures is different in some people.
Where does the petrosal nerve synapse?
However, the greater petrosal nerve doesn’t synapse inside the geniculate ganglion; it merely passes through.
What is the name of the nerve that connects the petrosal and deep petrosal nerves?
The combination of the greater petrosal and deep petrosal nerves is called the nerve of the pterygoid canal or the Vidian nerve. After the Vidian nerve leaves the pterygoid canal, it arrives at the pterygopalatine ganglion.
What nerve exits the skull?
After leaving the geniculate ganglion, the greater petrosal nerve continues forward toward the cheek. It passes through an opening called the hiatus of the facial canal, then along a narrow passage called the middle cranial fossa. It then exits the skull through the foramen lacerum.
What nerves are involved in tears?
The greater petrosal nerve branches off of the facial nerve in the skull. Along with a chain of other nerves, it innervates (provides nerve function to) the lacrimal gland, which produces tears. Also referred to as the greater superficial petrosal nerve, it’s related to structures called the pterygopalatine ganglion, the geniculate ganglion, ...
What is the facial nerve?
The facial nerve is the seventh cranial nerve (CN7) and one of the more complex ones. It’s formed by two roots that emerge from the brainstem at a spot called the pontomedullary junction. CN7 and its branches control most of the facial muscles and glands that produce saliva and tears.
Which nerve leaves the ganglion?
The parasympathetic fibers of the greater petrosal nerve leave the ganglion through several important branches: