The nasociliary nerve is part of the ophthalmic nerve. It crosses the optic nerve and passes through the orbit. It supplies the cornea.
What is the nasociliary nerve?
The nasociliary nerve is the first of three branches of the ophthalmic nerve. This is sensitive and part of the fifth cranial nerve, the trigeminal nerve. The trigeminal nerve supplies the entire face as well as much of the meninges. In particular, it innervates the masticatory muscles, teeth, gums, and lacrimal and salivary glands. The ophthalmic nerve, with its three branches, supplies separate areas of the upper visual field. These include the area of the eye, skin, forehead and nose. The three branches in turn bifurcate into three other branches. These are the nasociliary nerve, the frontal nerve, and the lacrimal nerve. The nasociliary nerve supplies the cornea to the eyeball. It also innervates the medial corners of the eye and the bridge of the nose. The mucosa of ethmoid cells, sphenoid sinus and nasal septum are also supplied by it. The eyeball is called the bulbus oculi. It is a spherical organ located in the orbit. The orbit is the eye socket in which the cornea is located. This is the cornea of the eye.
Anatomy and structure
The trigeminal nerve exits the lateral aspect of the pons and passes over the petrous pyramidal ridge. It forms the trigeminal ganglion. Posterior to the ganglion, the trigeminal nerve bifurcates into three branches, the ophthalmic nerve, the maxillary nerve, and the mandibular nerve. These three branches pass through three separate openings of the skull base. In the orbit, there is another bifurcation into three branches. The first of these is the nasociliary nerve. It passes over the optic nerve to the medial wall of the orbit. On the medial wall of the orbit, it passes ventrally. The nasociliary nerve is a branch to the ciliary ganglion. This supplies the bulbus oculi. In addition, it provides several smaller branches to supply the cornea. Finally, it forms two ethmodal nerves. These supply the ethmoid cells, the sphenoid sinus, and the nasal septum. The terminal branch of the nasociliary nerve exits at the medial corner of the eye. In this area, it supplies the skin and conjunctiva. It then innervates the skin on the bridge of the nose to the tip of the nose.
Function and tasks
The main function of the nasociliary nerve is to supply the eyeball, the mucosa around the nose, and parts of the skin in the visual field around the eye and nose. In the eyeball, it innervates the cornea. The cornea of the eye belongs to the anterior and highly curved portion of the eyeball. This is the transparent part that creates the conditions for sharp vision. Together with the optic nerve, the oculomotor nerve and the abducens nerve, it supplies the eye muscle and thus ensures its functional activity. The nasociliary nerve supplies the conjunctiva. This is transparent and consists of numerous vessels. It is the conjunctiva and covers the anterior surface of the eyeball with the exception of the cornea. The nasociliary nerve is a part that guarantees supply of the nasal mucosa. It also supplies the mucosa of the ethmoid as well as sphenoid sinuses. The cavities are a small nasal sinus. These air-filled cavities belong to the respiratory system and require mucosa for their work. The nasociliary nerve additionally innervates the ethmoid cells. Furthermore, the nasociliary nerve supplies the skin on the bridge of the nose to the tip of the nose. In this way, it supports the skin’s ability to function. This ranges from protection against external influences to the perception of sensations when touched. The inner corners of the eye are supplied by the nasociliary nerve. This area influences the entire lacrimal apparatus. This includes the lacrimal glands, the lacrimal fluid, and the lacrimal ducts. Even though the nasociliary nerve is not related to the formation of tears, the inner corners of the eyes are significantly related to the tear ducts.
Diseases
Lesions of the nasociliary nerve can lead to impaired corneal function. Thus, the ability to see sharply is severely impaired or no longer possible. The cornea is very sensitive to pain. Even the smallest injury or overexertion leads to severe pain or irritation. Impairment of its functionality affects the functionality of the eye muscle.It supplies the conjunctiva of the eye. If this supply is no longer sufficiently ensured, the likelihood of viruses accumulating in this area increases. These cause inflammation. Conjunctivitis is unpleasant and, moreover, contagious. Since the nasociliary nerve supplies large parts of the skin of the visual field, an impairment of its functionality can influence various diseases. The course of herpes zoster on the nose is associated with the nasociliary nerve. Herpes zoster is a viral disease. It is also known as shingles. The disease can occur on different parts of the face or neck. Usually, the disease as a whole is due to a weakening of the immune system. Nevertheless, its course depends on other influencing factors. The nasociliary nerve is responsible for supplying the mucous membrane in several sinuses as well as the nasal septum. If it is weakened and does not function, inflammations can occur. These can be acute, chronic, infectious, or allergic.
