The upper lip sensation is primarily provided by the infraorbital nerve, a branch of the maxillary nerve.
Sensory Innervation of the Upper Lip Explained
The perioral region, encompassing the upper lip, receives its sensory innervation from branches of the fifth cranial nerve, also known as the trigeminal nerve. More specifically, the maxillary and mandibular branches of the trigeminal nerve are responsible for this sensory input. The infraorbital nerve, as a terminal branch of the maxillary nerve, directly innervates the upper lip.
Here's a breakdown:
- Trigeminal Nerve (Fifth Cranial Nerve): The main nerve responsible for facial sensation.
- Maxillary Branch: One of the three main branches of the trigeminal nerve.
- Infraorbital Nerve: A branch of the maxillary nerve that provides sensation to the upper lip, lower eyelid, side of the nose, and cheek.
Clinical Significance
Understanding the nerve supply to the upper lip is important for several reasons:
- Dental Procedures: Dental procedures involving the upper teeth may require local anesthesia of the infraorbital nerve to numb the upper lip.
- Nerve Damage: Trauma or surgery in the midface can potentially damage the infraorbital nerve, resulting in numbness or altered sensation in the upper lip.
- Neurological Conditions: Certain neurological conditions can affect the trigeminal nerve, leading to pain or sensory disturbances in the areas it innervates, including the upper lip.
Table Summary
| Nerve | Branch of | Area Innervated |
|---|---|---|
| Infraorbital Nerve | Maxillary Nerve | Upper lip, lower eyelid, side of nose, cheek |
| Maxillary Nerve | Trigeminal Nerve | Midface |
| Mandibular Nerve | Trigeminal Nerve | Lower face |
