Singapore Med J 2007; 48(2) : e34
C a s e R e p o r t
The close proximity of the styloid process to
many of the vital neurovascular structures
in the neck makes it clinically significant.
Abnormal elongation of the styloid process may
cause compression on a number of vital vessels
and nerves related to it, producing inflammatory
changes that include continuous chronic pain in
the pharyngeal region, radiating otalgia, phantom
foreign body sensation (globus hystericus),
pain in the pharyngeal region, and dysphagia.
The normal length of the styloid process
is usually 2.0–2.5 cm long. We report a dry
human skull that showed bilateral styloid
processes measuring 6.0 cm on the right side
and 5.9 cm on the left side. The variation in
dimension of the process and its clinical implication
Keywords: dysphagia, Eagle’s syndrome, globus
hystericus, long styloid process, neck pain, styloid
Singapore Med J 2007; 48(2):e34–e36
The length of the styloid process normally varies
from 2.0 to 2.5 cm in adults.(1) The apex of the styloid
process is clinically important, because it is located
between internal and external carotid arteries. The
facial nerve runs anterior and medial to the styloid
process. The glossopharyngeal nerve exists through
jugular foramen and curves, in close proximity under
the styloid process. The accessory and vagus
nerves also run medial to the styloid process. The
approximation of the glossopharyngeal nerve
with the stylohyoid ligament is the basis for the
glossopharyngeal neurological symptoms seen in
Eagle’s syndrome.(2) The persistent angulations of the
cranial or styloid segment or Reichert’s cartilage and
its important neurovascular relationships may help
explain the symptomatology of Eagle’s syndrome.(3)
Eagle’s syndrome is an uncommon but important
cause of chronic head and neck pain.(4) The elongated
styloid process can cause craniofacial and cervical
pain, difficulties in
glossopharyngeal neuralgia, radiating pain into the
orbit and maxillary region.(4-6)
Eagle’s syndrome is a relatively common disorder
that is frequently misdiagnosed, and it occurs more
frequently in women.(7) Rizzatti-Barbosa reported that
an anatomical variant of stylohyoid ligament complex
was more frequent in the elderly female population,
although this abnormality was present in both sexes.
There was a greater tendency for the abnormality
to be present in patients between 60 and 79 years of
age.(8) The symptoms related to Eagle’s syndrome
can be confused with those attributed to a wide variety
of facial neuralgias(9) or oral, dental and temporo-
mandibular diseases.(10) We report a case of elongated
During a study on a fully ossified adult female skull
(i.e. prominent supercilliary arches, less prominent
glabella, smooth muscle attachments), belonging
to a patient from the Middle East, we found that the
styloid process was abnormally long (Fig. 1). The
lengths of the styloid process of both sides were
measured in centimetres from the base of the skull to
its tip. The lengths of both right and left styloid
processes were almost the same, measuring 6.0 cm on
the right side and 5.9 cm on the left side. This length is
about 150% longer than the length of a normal-sized
styloid process. The medial deviations were 24° and
26° for the right and left sides, respectively. The
anterior deviations for the right and left sides were 30°
Prabhu L V, Kumar A, Nayak S R, Pai M M, Vadgaonkar R, Krishnamurthy A,
Madhan Kumar S J
Centre for Basic
Prabhu LV, MS
Nayak SR, MSc
Pai MM, MD
Vadgaonkar R, MD
Krishnamurthy A, MD
Madhan Kumar SJ,
KS Hegde Medical
Kumar A, MS
Professor and Vice
Mr Soubhagya R
Tel: (91) 824 221 1746
Fax: (91) 824 242 1283
An unusually lengthy styloid process
Fig. 1 Photograph of the skull (right lateral view) shows the
right styloid process (arrows).
Singapore Med J 2007; 48(2) : e35
and 28°, respectively. The deviations were measured
using protractors, perpendicular to the skull in norma
The stylohyoid complex is composed of the styloid
process, stylohyoid ligaments and the stylomandibular
ligament.(11) The length of the styloid process has
been studied by Wang et a,(12) Basekim et al,(13)
Savranlar et al,(14) and Jung et al,(15) from radiographs
or three-dimension computed tomography. Data on
the osteometric values of the styloid process are
scanty. Thot et al reported that the length of the left
side styloid ranged from 0.7 to 1.6 cm, and on the right
side, from 0.8 to 2.4 cm. The average lengths for the
left and right styloids were 1.52 cm and 1.59 cm,
respectively, in Indian subjects.(16) Jung et al suggested
that the styloid process should be considered to
be elongated, when its length exceeds 45 mm.(15)
Keur et al stated that, if the length of the process or
the mineralised part of ligaments which appeared
in radiography was 30 mm or more, this could be
considered an elongated styloid process.(17) Thot et
al stressed that length in isolation is not a risk factor,
but that its combination with increased acuity in
deviation from the norm, both anteriorly and medially,
makes the elongated styloid process the sole cause of
The diagnosis can usually be made on physical
examination by digital palpation of the styloid process
in the tonsillar fosse, which exacerbates the pain and
with radiographical work-up. In addition, relief of
symptoms with injection of an anaesthetic solution
into the tonsilar fosse is highly suggestive of Eagle’s
syndrome.(18) The treatment of Eagle’s syndrome is
surgical removal of the offending calcified structure.
The entry path of the surgeon can be intra- or extra-
oral, considering the multitude and magnitude of
the major neurovascular tissues surrounding the
The stylohyoid process and ligament are derived
from the first and second brachial arches, in addition
to Reichert’s cartilage. It has been demonstrated that
during foetal development, Reichert’s cartilage links
the styloid bone to the hyoid bone. In the adult, the
stylohyoid ligament, which is normally composed of
dense fibrous connective tissue, may retain some of
its embryonic cartilage and thus have the potential
to become partially or completely ossified. If these
structures solidify, they can cause the pain and
suffering present in Eagle’s syndrome.(17,20) Steinmann
proposed various theories to explain ossification. These
were: (a) “Theory of reactive hyperplasia” – trauma
can cause ossification at the end of the styloid process
down the length of the styloid ligament, since the
styloid ligament contains remnants of its connective
tissue and fibrocartilaginous origins, the potential
for ossification remains; (b) “Theory of reactive
metaplasia” – an abnormal post-traumatic healing
response initiates the calcification of stylohyoid
ligament; and (c) “Theory of anatomic variance” – the
early elongation of the styloid process and ossification
of the styloid ligament are anatomical variations that
occur without recognisable trauma.(21)
In the present case, the skull possessed a styloid
process which is 6.0 cm long on the right side and
5.9 cm long on the left side. There is a paucity of
literature of such a long styloid process in the dry
human skull, which makes it unique. The present
variation might have caused severe pain and
psychotraumatic stress to the person. The embryogenesis
of the stylohyoid complex and the proper study on the
pathogenesis of the structures near the styloid process,
during trauma of the head and neck, will make Eagle’s
syndrome better understood and properly diagnosed.
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