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Infraorbital nerve

The infraorbital nerve is a significant sensory branch of the maxillary division (V2) of the trigeminal nerve (cranial nerve V). It provides sensation to the midface, including the lower eyelid, lateral nose, upper lip, and cheek. Passing through the infraorbital canal and emerging at the infraorbital foramen, the infraorbital nerve is crucial in clinical diagnosis, dental procedures, and maxillofacial imaging.

Synonyms:

  • Infraorbital branch of the maxillary nerve

  • V2 infraorbital nerve

  • Sensory branch of trigeminal nerve (V2)

  • Nerve of the infraorbital canal

Function:

  • Provides sensory innervation to:

    • Lower eyelid

    • Upper lip

    • Cheek and lateral nose

    • Mucosa of the upper lip, part of the nose, and upper gingiva

  • Plays a role in transmitting pain, touch, and temperature sensations from the midfacial region

  • Important in dental anesthesia for upper teeth and peri-oral procedures

MRI Appearance:

  • T1-weighted images (T1):

    • Infraorbital nerve appears as a small, low-to-intermediate signal structure within the infraorbital canal

    • Surrounded by high signal fat within the infraorbital canal, making the nerve visible as a linear dark structure

  • T2-weighted images (T2):

    • The nerve typically shows low-to-intermediate signal intensity

    • Best visualized against the high signal of the surrounding fat or orbital soft tissue

  • STIR (Short Tau Inversion Recovery):

    • The nerve may appear as a low signal linear structure, as fat signal is suppressed and pathology (such as edema or neuritis) may show high signal

    • Useful for detecting abnormal nerve signal, swelling, or infiltration

CT Appearance:

  • The infraorbital nerve itself is not directly visualized on CT due to its small size and soft tissue density

  • Infraorbital canal and foramen are well visualized as bony landmarks:

    • The infraorbital canal appears as a thin-walled tunnel in the maxilla, running from the inferior orbital fissure to the infraorbital foramen

    • The foramen is seen as an opening on the anterior maxilla, typically below the infraorbital rim

  • CT is important for assessing trauma, fractures, or tumors affecting the infraorbital nerve pathway

MRI images

Infraorbital nerve mri image