The pharyngeal plexus is a

nerve plexus A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve ple ...

located upon the outer surface of the

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

. It contains a motor component (derived from the vagus nerve (cranial nerve X)), a sensory component (derived from the glossopharyngeal nerve (cranial nerve IX)), and sympathetic component (derived from the superior cervical ganglion). The plexus provides motor innervation to most muscles of the

soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammals, the soft biological tissue, tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is ...

(all but the tensor veli palatini muscle) and most muscles of the

(all but the stylopharyngeus muscle). The

larynx The larynx (), commonly called the voice box, is an organ (anatomy), organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal ...

meanwhile receives motor innervation from the vagus nerve (CN X) via its external branch of the superior laryngeal nerve and its recurrent laryngeal nerve, and ''not'' through the pharyngeal plexus.

Anatomy

The pharyngeal plexus occurs upon the outer surface of the

- especially superficial to the middle pharyngeal constrictor muscle.

Afferents

It has the following components: * Motor – pharyngeal branch of vagus nerve (CN X) which arises from the superior portion of the inferior ganglion of vagus nerve, with the neuron cell bodies of its axons residing in the nucleus ambiguus. The pharyngeal branch ramifies upon reaching the superior border of the middle pharyngeal constrictor muscle. It is unclear whether the cranial root of accessory nerve (CN XI) * Sensory – pharyngeal branches of glossopharyngeal nerve. * Sympathetic

vasomotor Vasomotor refers to actions upon a blood vessel which alter its diameter. More specifically, it can refer to vasodilator action and vasoconstrictor action. Control Sympathetic innervation Sympathetic nerve fibers travel around the tunica media ...

– efferent fibres of the superior cervical ganglion. Because the cranial part of accessory nerve (CN XI) leaves the jugular foramen as a part of the CN X, it is sometimes considered part of the plexus as well.

Efferents/distribution

En route to their target tissues, outgoing fibres from the pharyngeal plexus at first either ascend upon the superior pharyngeal constrictor muscle or descend upon the inferior pharyngeal constrictor muscle, then ramify within the pharyngeal

muscular layer The muscular layer (muscular coat, muscular fibers, muscularis propria, muscularis externa) is a region of muscle in many organs in the vertebrate body, adjacent to the submucosa. It is responsible for gut movement such as peristalsis. The Latin ...

and

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

Motor

The pharyngeal plexus, with fibers from CN IX, CN X, and cranial part of CN XI, innervates all the muscles of the pharynx (except stylopharyngeus, which is innervated directly by a branch of CN IX). This includes the following muscles: palatopharyngeus, palatoglossus, musculus uvulae, the pharyngeal constrictors, salpingopharyngeus plus others.

Sensory

The pharyngeal plexus provides sensory innervation to most of the pharynx; it provides sensory innervation to the

oropharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

and laryngopharynx from CN IX and CN X. (The

nasopharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

above the pharyngotympanic tube and the

torus tubarius The torus tubarius (or torus of the auditory tube) is an elevation of the mucous membrane of the Pharynx#Nasopharynx, nasal part of the pharynx formed by the underlying base of the Eustachian tube, cartilaginous portion of the Eustachian tube, Eu ...

is innervated by CN V₂).

Sympathetic

Additional images

File:Slide5ggg.JPG, Pharyngeal plexus File:Slide2mmm.JPG, Pharyngeal plexus

References

{{DEFAULTSORT:Pharyngeal Plexus Of Vagus Nerve Nerve plexus Vagus nerve Human throat Nerves of the head and neck Pharynx