The nervus ethmoidalis posterior, also known as the posterior ethmoidal nerve, is a branch of the ophthalmic division of the trigeminal nerve (cranial nerve V). It is responsible for providing sensory innervation to the posterior ethmoidal air cells, part of the ethmoidal labyrinth within the cranial cavity.
This nerve arises from the nasociliary nerve, which is a branch of the ophthalmic nerve. After traversing the anterior ethmoidal canal in the ethmoid bone, it enters the posterior ethmoidal air cells. Within this structure, it branches into several filaments that innervate the mucous membrane, as well as the periosteum of the ethmoidal cells, transmitting sensory information from these areas to the brain.
The posterior ethmoidal nerve functions in transmitting general sensory information, such as pain, temperature, and touch, from the posterior ethmoidal air cells. Since the ethmoid bone is located in close proximity to other important structures within the cranial cavity, the nerve can also transmit referred pain from nearby regions (e.g., frontal sinuses, anterior ethmoidal air cells). This nerve's innervation plays a crucial role in maintaining proper sensory perception within these structures.
Understanding the anatomy and function of the nervus ethmoidalis posterior is essential in diagnosing and treating conditions that may involve the posterior ethmoidal air cells, such as sinusitis, nasal polyps, ethmoidal tumors, and trauma.
