Anatomy and Histology of the Frontalis Muscle

    loading  Checking for direct PDF access through Ovid



To determine the gross and histologic configurations of the medial and lateral frontalis muscle.


After making a midcoronal incision and bluntly dissecting to the orbital rim, the frontalis muscle was marked and measured. A protractor was used to measure the frontalis–orbicularis angle (FOA) and, when present, the angle of central bifurcation (AOB). Three strips of full-thickness forehead soft tissue measuring 0.5 cm × 8 cm were excised 3, 4.5, and 6 cm above the supraorbital notch and analyzed histologically for the presence of skeletal muscle fibers. Data were analyzed using 2-sample t tests, paired t tests, Pearson correlations, and mixed effect models. A p value of ≤ 0.05 was considered statistically significant.


Sixty-four hemifaces of 32 cadavers (16 males) were dissected. All specimens were Caucasian. The average age was 78.2 years (range, 56–102 years). The average FOA was 88.7° (13.0°), and the average AOB was 90.0° (26.4°). A visible midline bifurcation occurred in 28 of 32 subjects (88%) at an average height of 4.7 cm (range, 2.4–7.2 cm) superior to the supraorbital notch. Continuous skeletal muscle fibers were present within the midline bifurcation histologically in 89%, 75%, and 11% of specimens 3.5, 5.0, and 6.5 cm above the supraorbital notch, respectively. In 46% of individuals, skeletal muscle fibers were continuously present microscopically within the gross bifurcation.


While a medial frontalis muscle bifurcation occurs grossly in most senescent Caucasians, muscle fibers exist microscopically within this zone in nearly half of individuals.

Related Topics

    loading  Loading Related Articles