Corrugator Supercilii Muscle and Its Relationship with Neurovascular Structures of the Frontal Region: A Cadaveric Study.

BACKGROUND: The corrugator supercilii muscle (CSM) is a critical anatomical target for botulinum toxin injections and surgical interventions in migraine treatment and facial rejuvenation. However, complications such as sensory loss or vascular injury may arise due to its proximity to neurovascular structures. This study aims to delineate the precise anatomy of the CSM and its relationship with the supratrochlear (STN) and supraorbital nerves (SON) to enhance procedural safety.
METHODS: A cadaveric dissection was performed on 44 hemifaces of 22 formalin-fixed cadavers (11 male and 11 female). The CSM and adjacent neurovascular structures were dissected, photographed, and measured using ImageJ software. Morphometric parameters included distances related to the CSM, as well as branching patterns of the STN and SON were evaluated.
RESULTS: The CSM length was significantly longer in females (30.53 ± 2.60 mm; 28.93 ± 2.15 mm, p = 0.032). The STN exhibited complex branching (> 3 branches) in 48% of cases, with 13.6% piercing the CSM anteriorly. The SON medial branch pierced the CSM's lateral segments (46.5% 3rd segment; 53.5% 2nd segment). The supratrochlear artery crossed the CSM 14.84 ± 2.05 mm (females) and 15.43 ± 2.04 mm (males) from the midline, while the supraorbital artery lay 25.38 ± 3.76 mm (females) and 24.49 ± 4.55 mm (males) lateral to the midline.
CONCLUSIONS: The CSM's intimate relationship with the STN, SON, and associated vessels underscores the risk of iatrogenic injury during forehead procedures. Anatomical variations in nerve branching and muscle morphology highlight the need for individualized approaches to botulinum toxin injection and surgical resection. These findings may reduce complications and improve outcomes in migraine surgery and aesthetic interventions.
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