ASOPRSFall Scientific SymposiumSyllabus
104
EyelidSession II
Moderator:Tanuj Nakra,MD
10:40 am
Anatomy andHistologyof theFrontalisMuscle
BryanCostin
1
, ThomasPlesec
2
, NattaSakolsatayadorn
3
, Tal Rubinstein
1
, JenniferMcBride
4
, JulianPerry
1
.
1
Cole Eye Institute,
ClevelandClinic, Cleveland, OH, UnitedStates,
2
Department of AnatomicPathology, ClevelandClinic, Cleveland, OH, United
States,
3
Department of Ophthalmology,MedicineSiriraj Hospital, Bangkok, Thailand,
4
Department of Anatomy, ClevelandClinic,
Cleveland, OH, UnitedStates
Introduction:
The occipitofrontalismuscle represents the onlymuscle capable of elevating the eyebrow and critically determines
the structure, function, and cosmesis of the forehead, eyebrow, and eyelid.
1-5
Despite its importance, a PubMed search inDecember
2013 using the search parameters ‘frontalis,’ ‘eyebrow position,’ ‘eyebrow ptosis,’ ‘brow position,’ and ‘brow ptosis’ yielded only
7 reports on the anatomy of this region.We sought to determine the gross and histological configurations of themedial and lateral
frontalismuscle to improve our understanding and treatment of forehead and periocular aging changes.
Methods:
Aftermaking amid-coronal incision and bluntly dissecting to the orbital rim, the frontalismusclewasmarked and
measured.A protractor was used tomeasure the frontalis-orbicularis angle (FOA) (Figure 1,2) and,when present, the angle of central
bifurcation (AOB) (Figure 3).Three strips of full thickness forehead soft tissue 0.5 cm x 8 cmwere excised 3 cm, 4.5 cm, and 6 cm
above the supraorbital notch and analyzed histologically for the presence of skeletal muscle fibers (Figure 4). Datawere analyzed
using two-sample t-tests, paired t-tests, Pearson correlations, andmixed effect models.A p-value of
≤
0.05was considered
statistically significant.
Results:
Sixty-four hemifaces of 32 cadavers (16male) were dissected.All specimenswere Caucasian.Average agewas 78.2 years
(range, 56 - 102 years).Average FOAwas 88.7° (13.0°) and averageAOBwas 90.0° (26.4°).A visiblemidline bifurcation occurred
in 28/32 (88%) subjects at an average height of 4.7 cm (range, 2.4 - 7.2 cm) superior to the supraorbital notch. Continuous skeletal
muscle fiberswere present within themidline 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 fiberswere continuously present microscopically
within the gross bifurcation.
Conclusions:
While amedial frontalismuscle bifurcation
occurs grossly inmost senescent Caucasians,muscle
fibers exist microscopicallywithin this zone in nearly half
of individuals.The frontalis orbicularis angle (FOA) and
insertion (FOI) display polymorphism and variations in
these structuresmay explain eyebrow position and contour
aswell as eyebrowmalpositions and rhytides.
References:
1.MatarassoA,Terino EO. Forehead-brow
rhytidoplasty: reassessing the goals. Plast Reconstr Surg
1994;93:1378-91.
2. Paul MD,The evolution of the brow lift in aesthetic
plastic surgery. Plast Reconstr Surg. 2001;108:1409-24.
3. Presti P,Yalamanchii H, Honrade CP. Rejuvenation
of the aging upper third of the face. Facial Plast Surg
2006;22:91-6.
4. Hetzler L, Sykes J.The brow and forehead periocular rejuvenation. Facial Plast SurgClinNAm2010;18:375-384.
5. Lorenc ZP, Smith S, NestorM, et al. Understanding the functional anatomy of the frontalis and glabellar complex for optimal
aesthetic botulinum toxin typeA therapy. Aesth Plast Surg 2013;37:975-983.
DetailedProgram
—Friday,October 17, 2014
