Normative data for dimensions of the frontal and infraorbital nerves

To present a series of normative measurements for the width of the frontal and infraorbital nerve branches of V1 and V2, respectively.

Cadaveric dissection study of 15 embalmed cadaver heads (30 orbits). The frontal nerve was excised en bloc from the superior orbital rim to the superior orbital fissure. Similarly, the infraorbital nerve was excised en bloc from the inferior orbital rim to the orbital apex. Measurements were recorded of the maximal width of the frontal nerve, infraorbital nerve within the orbital floor, and pterygopalatine segment of the maxillary nerve. Any value greater than 2 standard deviations (SD) above the mean value, was defined as nerve enlargement.

The mean transverse diameter of the frontal nerve was 2.27 ± 0.66 mm (1 SD). The mean transverse diameter of the infraorbital nerve branch, and the maxillary nerve within the pterygopalatine fossa, was 3.31 ± 0.68 mm (1 SD) and 3.59 ± 0.76 mm (1 SD), respectively. The upper limit of normal, defined as 2 SD above the mean value, for the widths of the frontal nerve, infraorbital nerve, and pterygopalatine segment of V2 widths were 3.59 mm, 4.67 mm, and 5.10 mm, respectively.

The frontal and infraorbital nerves are implicated in various inflammatory and neoplastic orbital pathologies. Defining the normative data for width is important to compare with pathological states.