The nose is innervated by several cranial nerves, each playing a vital role in its function. These include sensory nerves responsible for feeling and the olfactory nerve responsible for smell.
Sensory Innervation of the Nose
The primary sensory nerves supplying the nose are branches of the trigeminal nerve (CN V), specifically:
- Ophthalmic nerve (CN V1): This branch provides sensory information from the skin of the medial eyelids and the side of the nose via its infratrochlear and ethmoidal branches. The external nasal branch of the anterior ethmoid nerve also contributes to the external nose's sensory innervation.
- Maxillary nerve (CN V2): This nerve supplies sensation to the lateral dorsum and alae (wings) of the nose.
Additionally, the nasociliary nerve, a branch of the ophthalmic nerve, contributes sensory perception to the mucous membranes of the nasal cavity.
Motor Innervation of the Nose
The facial nerve (CN VII) controls the muscles of facial expression, including those that affect the nose's movement.
Olfactory Innervation
The sense of smell is mediated by the olfactory nerve (CN I). These olfactory sensory neurons are located in the upper part of the nasal cavity. They transmit signals directly to the olfactory bulb in the brain.
Autonomic Innervation
The autonomic nervous system also significantly innervates the nose and paranasal sinuses, influencing functions like blood vessel constriction and mucus secretion. This intricate network plays a crucial role in nasal physiology, although the specific nerves involved are complex and beyond the scope of a concise answer.
In summary, the nose receives sensory input from branches of the trigeminal nerve (CN V), motor input from the facial nerve (CN VII), and the sense of smell is conveyed by the olfactory nerve (CN I). The autonomic nervous system also plays a critical but less directly identifiable role in nasal functions.
