The zygomaticotemporal branch of the trigeminal nerve

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Cosmetic
The Zygomaticotemporal Branch of the
Trigeminal Nerve: An Anatomical Study
Ali Totonchi, M.D., Nazly Pashmini, M.D., and Bahman Guyuron, M.D.
Cleveland, Ohio
dition, the number and locations of the
accessory branches of the trigeminal nerve
were recorded. On the left side, the average
distance of the emergence site of the main
zygomaticotemporal branch of the trigeminal nerve from the palpebral fissure was
16.8 mm (range, 12 to 31 mm) in the posterolateral direction and an average of 6.4
mm (range, 4 to 11 mm) in the cephalad
direction. On the right side, the average
measurements for the main branch were
17.1 mm (range, 15 to 21 mm) in the lateral
direction and 6.65 mm (range, 5 to 11 mm)
in the cephalic direction. Three types of
accessory branches were found in relation
to the main branch: (1) accessory branch
cephalad, (2) accessory branch lateral, and
(3) accessory branches in the immediate
vicinity of the main branch. This anatomical information has proven colossally helpful in injection of botulinum toxin A in the
temporalis muscle to eliminate the trigger
sites in the parietotemporal region and surgical management of migraine headaches
triggered from this zone. (Plast. Reconstr.
Surg. 115: 273, 2005.)
This study was conducted to determine
the site of emergence of the zygomaticotemporal branch of the trigeminal nerve
from the temporalis muscle and to identify
the number of its accessory branches and
their locations. A pilot study, conducted on
the same number of patients, concluded
that the main zygomaticotemporal branch
emerges from the deep temporal fascia at
a point on average 17 mm lateral and 6 mm
cephalad to the lateral palpebral commissure, commonly referred to as the lateral
canthus. These measurements, however,
were obtained after dissection of the temporal area, rendering the findings less reliable. The current study included 20 consecutive patients, 19 women and one man,
between the ages of 26 and 85 years, with an
average age of 47.6 years. Those who had a
history of previous trauma or surgery in the
temple area were excluded. Before the start
of the endoscopic forehead procedure, the
likely topographic site of the zygomaticotemporal branch was marked 17 mm lateral
and 6 mm cephalad to the lateral orbital
commissure on the basis of the information
extrapolated from the pilot study. The surface mark was then transferred to the
deeper layers using a 25-gauge needle
stained with brilliant green. After endoscopic exposure of the marked site, the distance between the main branch of the trigeminal nerve or its accessory branches and
the tattoo mark was measured in posterolateral and cephalocaudal directions. In ad-
Migraine headache affects approximately
18.2 percent of the female population and 6.5
percent of the male population in the United
States alone.1 One of every four households has
a member who suffers from migraine headaches.1 Recent clinical studies suggest that peripheral stimulation of the terminal branches
of the trigeminal nerve by the surrounding
From the Division of Plastic Surgery, Case Western Reserve University, and the American Migraine Center. Received for publication September
16, 2003; revised January 15, 2004.
DOI: 10.1097/01.PRS.0000145639.42257.4F
273
274
PLASTIC AND RECONSTRUCTIVE SURGERY,
muscles may cause central sensitization and
trigger a migraine headache.2,3
Studies conducted by the senior author of
this article (Guyuron) have both retrospectively
and prospectively demonstrated that removal of
the glabellar muscle group (corrugator supercilii, depressor supercilii, and procerus) eliminates
or reduces migraine headaches in properly selected patients.2,4 This study was conducted to
determine the topographic site of the zygomaticotemporal branch of the trigeminal nerve as it
exits from the deep temporal fascia, to facilitate
both injection of botulinum toxin and identification of the nerve branches during the surgical
procedures.
ANATOMY
OF THE
ZYGOMATICOTEMPORAL BRANCH
TRIGEMINAL NERVE
OF THE
The zygomaticotemporal nerve is a branch
of the maxillary division of the trigeminal
nerve. The maxillary division is the intermediate branch of the trigeminal nerve and is completely sensory in nature. It emerges from the
trigeminal ganglion between the ophthalmic
and mandibular nerves and extends anteriorly
in a horizontal plane lateral and caudal to the
cavernous sinus. It then traverses the foramen
rotundum, crossing the upper part of the
pterygopalatine fossa, inclines laterally on the
posterior surface of the orbital process of the
palatine bone, and then courses on the upper
part of the posterior surface of the maxilla.
The zygomatic branch of this nerve originates in the pterygopalatine fossa, enters the
orbit through the inferior orbital fissure, travels along its lateral wall, and bifurcates into
zygomaticotemporal and zygomaticofacial
branches (Fig. 1). The zygomaticotemporal
nerve passes along the inferolateral angle of
the orbit, provides a ramus to the lacrimal
gland, traverses a bony canal in the zygomatic
bone, and enters into the temporal fossa. This
branch then ascends between the bone and the
temporalis muscle (Fig. 2). It pierces the deep
temporal fascia approximately 2 cm above the
zygomatic arch to innervate the skin of the
temporal area. It communicates with the facial
and auriculotemporal nerves. As it pierces the
temporal fascia, it sends a slender twig between
the two fascial layers toward the lateral angle of
the orbit. The lacrimal branch carries parasympathetic postganglionic fibers from the pterygopalatine ganglion to the lacrimal gland.5 A
horizontal branch extends from this nerve to
January 2005
FIG. 1. Illustration of the zygomaticotemporal branch of
the trigeminal nerve. AT, auriculotemporal; ZTBTN, zygomaticotemporal branch of the trigeminal nerve; ZFTBN, zygomaticofacial branch of the trigeminal nerve.
connect with the branches of the auriculotemporal nerve.
PATIENTS
AND
METHODS
Initially, 20 patients, 19 women and one
man, who underwent endoscopic forehead surgery were included in the pilot portion of the
study. After dissection of the temple region
and exposure of the zygomaticotemporal
branch of the trigeminal nerve, a 25-gauge needle was passed through the skin at a 90-degree
angle to meet the nerve under observation
through the endoscope. The distance of the
needle from the lateral commissure was then
measured in the horizontal (posterolateral)
and vertical (cephalocaudal) dimensions. The
actual distance of the main branch of the zygomaticotemporal nerve where it pierced the
deep temporal fascia was measured and was on
average 17 mm posterolateral and 6 mm cephalad to the lateral orbital commissure. However, this pilot study did not include identification of the accessory branches. Furthermore,
because the measurements were obtained after
dissection of the area, one could not rely sufficiently on the findings. To overcome this
shortcoming, the methodology was altered
during the main study.
In the main study, an additional 20 consecutive patients, 19 women and one man who
underwent primary endoscopic forehead rejuvenation for the treatment of migraine headaches, were included. Patients who sustained
previous trauma to this region or had undergone surgery in the forehead area were excluded from the study. Before starting the endoscopic forehead rejuvenation, the potential
Vol. 115, No. 1 /
275
TRIGEMINAL NERVE
FIG. 2. Endoscopic (above) and open (below) views of the
zygomaticotemporal nerve as it emerges from the temporalis
muscle. ZTBTN, zygomaticotemporal branch of the trigeminal nerve; DTF, deep temporal fascia; SON, supraorbital
nerve.
site of the zygomaticotemporal branch of the
trigeminal nerve was marked on the basis of
the pilot study. A point was selected exactly 17
mm posterolateral and 6 mm cephalad to the
lateral orbital commissure. Using a 25-gauge
needle stained with brilliant green solution,
the skin marking was then transferred to the
deep temporal fascia. Next, a routine endoscopic approach was used to expose the deep
temporal fascia and dissect the temporal region, preserving the integrity of the zygomaticotemporal branches. Any variation of the
nerve anatomy was identified and the distance
of aberrant branches was measured from the
tattoo point on the fascia in the horizontal
(posterolateral) and sagittal planes. The results
were then tabulated and analyzed.
on the right. None of the patients in this consecutive series had to be excluded for the reasons of previous trauma or forehead surgery.
Eight patients had only one main branch on
each side. Twelve patients had at least one
additional accessory branch on either side.
Three patients had two accessory branches.
When the overall results were considered,
the main zygomaticotemporal branch of the
trigeminal nerve was on average 16.9 mm
(range, 12 to 31 mm) posterolateral to the
palpebral commissure and 6.5 mm (range, 4 to
11 mm) cephalad to the lateral palpebral commissure. On the left side, the average distance
of the main zygomaticotemporal branch of the
trigeminal nerve from the lateral orbital commissure, judged by the location of the tattoo
mark, was 6.4 mm (range, 4 to 11 mm) in a
cephalad direction. The distance from the lateral orbital commissure was 16.8 mm (range,
12 to 31 mm) in a posterolateral direction (Fig.
3). On the right side, the average measurement from the lateral orbital commissure was
6.65 mm (range, 5 to 11 mm) in a cephalad
direction and 17.1 mm (range, 15 to 21 mm) in
a posterolateral direction (Fig. 4).
The accessory nerves were found in three
distinctive sites: superior to the main branch,
posterolateral to the main branch, and immediately adjacent to the main branch (Table I).
On the left side, the accessory nerve distribution was found in 10 patients:
TABLE I
Right-Side, Left-Side, and Bilateral Average Measurements
and Number of Accessory Nerves
Left
Right
Bilateral
Average
Posterolateral
(mm)
Average
Cephalic
(mm)
No. of
Accessory Nerves
16.8
17.1
16.95
6.4
6.65
6.525
12 in 10 patients
13 in 11 patients
25 in 12 patients
RESULTS
The 20 patients in the main study ranged in
age between 26 and 65 years, with the average
age being 47.6 years old. A total of 65 measurements were recorded, 32 on the left side and 33
FIG. 3. The distribution of the left-side zygomaticotemporal nerve emergence point from the temporalis fascia.
276
● Accessory branches cephalad to the main
branch were found in three cases, and one
of the patients had two accessory branches in
this area. These were located approximately 16
mm (range, 12 to 20 mm) posterolateral and
12.2 mm (range, 11 to 16 mm) cephalad to the
lateral orbital commissure.
● Accessory branches lateral to the main
branch area (on a line horizontally extending posterolateral from the main branch)
were found in four cases. The average measurement was 34.2 mm (range, 30 to 39 mm)
posterolateral and 6.7 mm (range, 6 to 8
mm) cephalad to the palpebral fissure.
● Accessory branches adjacent to the main
branch were found in three cases, and one
of the patients was noted to have two accessory branches in this area. The average measurement was 17.7 mm (range, 15 to 20 mm)
lateral and 6 mm (range, 4 to 9 mm) cephalad to the palpebral fissure.
Accessory branches cephalad to the main
branch on the right were found in six patients,
and two patients had two accessory branches.
The average measurements were 15.7 mm
(range, 15 to 17 mm) posterolateral and 16.5
mm (range, 13 to 24 mm) cephalad to the
palpebral fissure. Accessory branches posterolateral to the main branch were found in four
patients. The average measurements were 28.7
mm (range, 26 to 33 mm) posterolateral to the
palpebral commissure and 6.0 mm (range, 6 to
6 mm) cephalad to the orbital fissure. Accessory branches adjacent to the main branch
were found in only one case on the right side,
located 19 mm posterolateral and 5 mm cephalad to the orbital fissure.
The branches that were found posterolaterally were all directed horizontally to join the
auriculotemporal branch of the mandibular division. The patients who did not have a sepa-
FIG. 4. The distribution of the right-side zygomaticotemporal nerve emergence point from the temporalis fascia.
PLASTIC AND RECONSTRUCTIVE SURGERY,
January 2005
rate branch piercing the deep temporal fascia
all had the horizontal branch emerging from
the main zygomaticotemporal branch of the
trigeminal nerve above the fascia. This indicates a variation in branching of the zygomaticotemporal branch of the trigeminal nerve,
whereby in some patients the horizontal
branch arises from this nerve above the deep
temporal fascia and in some patients below the
fascia.
DISCUSSION
On the basis of our studies, the glabellar
muscle group constitutes the most common
trigger zone for migraine headaches, stimulating the supratrochlear and supraorbital
branches. The second most likely trigger site of
migraine headaches is located in the temporal
region, where the zygomaticotemporal branch
of the trigeminal nerve becomes irritated by
being compressed by the temporalis muscle.6
Studies have shown that resection of the corrugator supercilii muscle and avulsion of the
zygomaticotemporal nerve can lead to complete elimination of or significant improvement in migraine headaches.7 During surgery,
an approximately 3-cm-long segment of the
nerve is avulsed. This essentially removes the
portion of the nerve that travels within or next
to the muscle. The transected end retracts into
the orbit. This study was conducted to identify
the emergence point of the zygomaticotemporal branch of the trigeminal nerve from the
deep temporal fascia to more easily locate the
nerve during surgery and to provide a reliable
topographic reference for injection of botulinum toxin A.
Using the t test for paired samples, we concluded that there was no statistical difference
FIG. 5. Photograph demonstrating the method of botulinum toxin A injection in temporal area.
Vol. 115, No. 1 /
277
TRIGEMINAL NERVE
between the left-side and the right-side measurements. Because of an insufficient number
of men (one of 20), it was not possible to
investigate whether gender was a factor in the
topography of the zygomaticotemporal branch
of the trigeminal nerve or its accessory branching. Our predominantly female study population somewhat parallels the gender trend of
migraine sufferers in the general public, with a
female-to-male ratio of approximately 3:1.
There is a dearth of literature describing the
site of emergence of the zygomaticotemporal
branch of the trigeminal nerve from the deep
temporal fascia.
It is fascinating that a hollow area surrounds
the point of emergence of the zygomaticotemporal branch of the trigeminal nerve and can
be readily located by palpation. To inject this
area, 12.5 to 25 units of botulinum toxin A is
diluted in 0.5 cc of saline in a 3-cc syringe
attached to a 30-gauge, 1-inch-long needle.
With the left index finger (for a right-handed
person) positioned in the nerve emergence
site from the deep temporal fascia (Fig. 5), the
needle is passed through the skin and the subcutaneous tissue, starting approximately 2 cm
posterolateral to the left index finger and advanced through the deep temporal fascia. The
location of this structure can be felt distinctly
by a subtle increase in resistance as the needle
passes through it, and botulinum toxin A is
injected generously into this area and the
deeper portion of the muscle. The needle can
then be directed cephalad, posteriorly, and
caudally, injecting the full extent of the muscle, if one finds it necessary on the basis of the
clinical findings. The authors have noted a
change in range of motion or strength of mandibular closure. However, the most important
aspect of this injection is paralysis of the temporalis muscle fibers immediately adjacent to
the zygomaticotemporal branch of the trigeminal nerve. In addition, the information
extrapolated from this study has been beneficial during surgery for the elimination of or
improvement in migraine headaches in patients with refractory migraine headache.
The surface marking properly guides the surgeon to the site of emergence of the zygomaticotemporal branch of the trigeminal
nerve from the deep temporal fascia, thus
simplifying the surgical procedure. Because
injection of botulinum toxin A diffuses in a
radius of 11⁄2 cm, despite the variation in
anatomy, it becomes efficacious by injection
into the fascia penetration site. Further anatomical studies are in process to delineate
the intramuscular branching of this nerve
and the other nerves within the temporalis
muscle.
Bahman Guyuron, M.D.
29017 Cedar Road
Lyndhurst, Ohio 44124
[email protected]
REFERENCES
1. Lipton, R. B., Stewart, W. F., Diamond, S., et al. Prevalence and burden of migraine in the United States:
Data from the American Migraine Study II. Headache
41: 646, 2001.
2. Guyuron, B. Corrugator supercilii muscle resection and
relief of migraine headache: Findings of a retrospective study. Todays Ther. Trends 19: 59, 2001.
3. Burstein, R., Cutrer, M. F., and Yarnitsky, D. The development of cutaneous allodynia during a migraine
attack clinical evidence for the sequential recruitment
of spinal and supraspinal nociceptive neurons in migraine. Brain 123: 1703, 2000.
4. Malick, A., and Burstein, R. Peripheral and central sensitization during migraine. Funct. Neurol. 15 (Suppl.
3): 28, 2000.
5. Williams, P. L., Warwick, R., Dyson, M., et al. Gray’s
Anatomy, 37th Ed. New York: Churchill Livingstone,
1989. Pp. 1098-1103.
6. Guyuron, B., Kriegler, J. S., Tucker, T., Davis, J., and
Amini, S. Comprehensive treatment of migraine
headaches. Plast. Reconstr. Surg. 115: 1, 2005.
7. Guyuron, B., Tucker, T., and Davis, J. Surgical treatment of migraine headaches. Plast. Reconstr. Surg. 109:
2183, 2002.
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