Posterior ethmoidal nerve

Diagram of the nerves of the orbit, including the posterior ethmoidal nerve.

The posterior ethmoidal nerve is a branch of the nasociliary nerve, which itself is a branch of the ophthalmic nerve (CN V1), a division of the trigeminal nerve (CN V). This nerve plays a crucial role in the sensory innervation of the ethmoidal air cells and the sphenoidal sinus.

Anatomy

The posterior ethmoidal nerve arises from the nasociliary nerve as it traverses the orbit. It exits the orbit through the posterior ethmoidal foramen, which is located on the medial wall of the orbit. Once it passes through this foramen, the nerve enters the cranial cavity and provides sensory innervation to the mucous membranes of the posterior ethmoidal air cells and the sphenoidal sinus.

Function

The primary function of the posterior ethmoidal nerve is to supply sensory fibers to the mucosa of the posterior ethmoidal air cells and the sphenoidal sinus. This sensory innervation is important for the perception of pain and other sensations in these areas, which can be significant in conditions such as sinusitis.

Clinical Significance

In clinical practice, the posterior ethmoidal nerve is relevant in the context of sinus surgery and endoscopic sinus surgery. Surgeons must be aware of the location of this nerve to avoid damaging it during procedures involving the ethmoidal air cells or the sphenoidal sinus. Damage to the nerve can result in loss of sensation or chronic pain in the areas it supplies.

Related Pages

• Nasociliary nerve
• Ophthalmic nerve
• Trigeminal nerve
• Ethmoidal air cells
• Sphenoidal sinus