Anterior ethmoidal nerve
Nerve of the nose
From Wikipedia, the free encyclopedia
The anterior ethmoidal nerve is a nerve of the head.[1] It is a sensory branch of the nasociliary nerve (itself a branch of the ophthalmic nerve (CN V1)).[2] It arises in the orbit, and enters first the cranial cavity and then the nasal cavity.[3] It provides sensory innervation to part of the meninges, nasal cavity, and part of the skin of the nose.[4] The nerve is relevant in conditions involving nasal sensation and in surgical procedures of the skull base and nasal cavity.[5]
| Anterior ethmoidal nerve | |
|---|---|
The ophthalmic artery and its branches. (Nerve not pictured, but location is similar to artery.) | |
| Details | |
| From | Nasociliary nerve |
| Innervates | Meninges, nasal cavity, skin of nose |
| Identifiers | |
| Latin | nervus ethmoidalis anterior |
| TA98 | A14.2.01.030 |
| TA2 | 6208 |
| FMA | 52675 |
| Anatomical terms of neuroanatomy | |
Structure
Origin
The anterior ethmoidal nerve is a terminal branch of the nasociliary nerve, a branch of the ophthalmic nerve (CN V1), itself a branch of the trigeminal nerve (CN V).[6] It branches near the medial wall of the orbit.
Course
It passes through the anterior ethmoidal canal alongside the anterior ethmoidal artery[1]: 780 and vein[1]: 566 to emerge in anterior cranial fossa through the anterior ethmoidal foramen[1]: 1464.e13 (at the junction of the cribiform plate of ethmoid bone and orbital part of frontal bone[1]: 566 ).
Within the cranial cavity, it passes anterior-ward (external to the dura mater) along a groove upon the superior surface of the cribriform plate. It descends through an aperture situated lateral to the crista galli to reach the nasal cavity.[1]: 1464.e13
In the nasal cavity, it passes along a groove upon the internal aspect of the nasal bone, and issuing the medial and lateral internal nasal branches.[1]: 1464.e13
It is continued as the external nasal nerve beyond the inferior margin of the nasal bone.[1]: 1464.e13
Distribution
Within the anterior cranial fossa, it gives sensory fibers to the meninges to provide sensory innervation to part of the meninges.[7]
Its medial internal nasal branch innervates the superior and anterior portions of the nasal septum.[1]: 1464.e13
Its lateral internal nasal branch innervates the anterior portion of the lateral nasal wall.[1]: 1464.e13
It gives off branches to the roof of the nasal cavity, and bifurcates into a lateral internal nasal branch and medial internal nasal branch. It sends sensory fibers to the anterior ethmoid air cells and the middle ethmoidal air cells.[4]
Its terminal branch - the external nasal nerve - innervates skin of the nose between the nasal bones superiorly and the tip of the nose inferiorly, except the alar portion surrounding the external nares.[1]: 1464.e13
Function
It is involved in the diving reflex.[8]
Disease
Chronic pain in this region is known as Anterior Ethmoidal Nerve Syndrome, or AENS.[9] One cause of this is compression of the surrounding nerve which causes sphenopalatine ganglion neuralgia, with similar clinical findings of a cluster headache, outside of further nasal symptoms.[10] Potential treatments include the injection of anesthetics or, in more serious cases, a partial turbinectomy. The syndrome was featured in season 3, episode 5 of Grey's Anatomy.
