Morphometric Evaluation of the Frontal Migraine Trigger Site

Migraine headache has been attributed to specific craniofacial peripheral nerve trigger sites. Some have postulated that hypertrophy of the corrugator muscles causes compression of the supraorbital and supratrochlear nerves, resulting in migraine headache. This study uses morphometric evaluation to determine whether corrugator anatomy differs between patients with migraine headache and control subjects.

A retrospective review identified patients with and without migraine headache who had a recent computed tomographic scan. Morphometric evaluation of the corrugator supercilii muscles was performed in a randomized and blinded fashion on 63 migraine headache and 63 gender-matched control patients using a three-dimensional image-processing program. These images were analyzed to determine whether corrugator size differed between migraine and control patients.

There was no difference in mean corrugator volume or thickness between migraine and control patients. The mean corrugator volume was 1.01 ± 0.26 cm compared with 1.06 ± 0.27 cm in control patients (p = 0.258), and the mean maximum thickness was 5.36 ± 0.86 mm in migraine patients compared with 5.50 ± 0.91 mm in controls (p = 0.359). Similarly, subgroup analysis of 38 patients with frontal migraine and 38 control subjects demonstrated no difference in corrugator size. Further subgroup analysis of nine patients with unilateral frontal migraine showed no difference in corrugator size between the symptomatic side compared with the contralateral side.

Muscle hypertrophy itself does not play a major role in triggering migraine headache. Instead, factors such as muscle hyperactivity or peripheral nerve sensitization may be more causative.