The geniculate ganglion (from Latin genu, for "knee") is an L-shaped collection of fibers and sensory neuron

Sensory neuron

Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...

s of the facial nerve

Facial nerve

The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...

 located in the facial canal

Facial canal

The facial canal is a Z-shaped canal running through the temporal bone from the internal acoustic meatus to the stylomastoid foramen. In humans it is approximately 3 centimeters long, which makes it the longest human osseous canal of a nerve...

 of the head

Head

In anatomy, the head of an animal is the rostral part that usually comprises the brain, eyes, ears, nose and mouth . Some very simple animals may not have a head, but many bilaterally symmetric forms do....

. It receives fibers from the motor, sensory, and parasympathetic

Parasympathetic nervous system

The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system . The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously...

 components of the facial nerve and sends fibers that will innervate the lacrimal gland

Lacrimal gland

The lacrimal glands are paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper, outer portion of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Inflammation of the lacrimal glands is called...

s, submandibular gland

Submandibular gland

The paired submandibular glands are salivary glands located beneath the floor of the mouth. In humans, they account for 70% of the salivary volume and weigh about 15 grams. Unstimulated in humans, the percentage contribution to whole saliva; ~25% Parotid, Submandibular and Sublingual ~ 67% and...

s, sublingual gland

Sublingual gland

The sublingual glands are salivary glands in the mouth.They lie anterior to the submandibular gland under the tongue, beneath the mucous membrane of the floor of the mouth.They are drained by 8-20 excretory ducts called the ducts of Rivinus....

s, tongue

Tongue

The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...

, palate

Palate

The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

, pharynx

Pharynx

The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

, external auditory meatus, stapedius

Stapedius

The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes....

, posterior belly of the digastric muscle

Digastric muscle

The digastric muscle is a small muscle located under the jaw. so digastric muscles are muscle fibers in ligament of treitz ,omohyoid , occipitofrontalis....

, stylohyoid muscle

Stylohyoid muscle

The stylohyoid muscle is a slender muscle, lying anterior, and superior of the posterior belly of the digastric muscle. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid bone backwards and elevate the tongue....

, and muscles of facial expression

Facial expression

A facial expression one or more motions or positions of the muscles in the skin. These movements convey the emotional state of the individual to observers. Facial expressions are a form of nonverbal communication. They are a primary means of conveying social information among humans, but also occur...

.

The geniculate ganglion contains special sensory neuronal cell bodies for taste, from fibers coming up from the tongue through the chorda tympani and from fibres coming up from the roof of the palate through the greater petrosal nerve (MJ Fitzgerald et al Clinical Neuroanatomy and Neuroscience). Sensory and parasympathetic inputs are carried into the geniculate ganglion via the nervus intermedius

Nervus intermedius

The nervus intermedius, or intermediate nerve, is the part of the facial nerve located between the motor component of the facial nerve and the vestibulocochlear nerve . It contains the sensory and parasympathetic fibers of the facial nerve...

. Motor fibers are carried via the facial nerve proper. The greater petrosal nerve, which carries sensory fibers as well as preganglionic parasympathetic fibers, emerges from the anterior aspect of the ganglion.

The geniculate ganglion is one of several ganglia of the head and neck. Like the others, it is a bilaterally distributed structure, with each side of the face having a geniculate ganglion.

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