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SEMINAR ONSEMINAR ON
CEPHALOMETRICS : HISTORY, EVOLUTIONCEPHALOMETRICS : HISTORY, EVOLUTION
Ever since God created man in His image, man has been trying to change man
into his image. Attempts to change facial appearance are recounted throughout recorded
history. The question of what is a normal face, as that of what constitutes beauty, will
probably never be answered in a free society.
Orthodontists, in their attempts to change facio-oro-dental deviations from
accepted norms, have adopted cephalometric measurement, a method long employed in
physical anthropology. With the introduction of roentgenography, it was inevitable that
this procedure should be employed as a medium for the purpose of roentgenographic
Cephalometric radiography was introduced in to orthodontics during the 1930s.
Cephalometry had its beginnings in craniometry. Craniometry is defined in the
Edinburgh encyclopedia of 1813 as “the art of measuring skulls of animals so as to
discover their specific differences”. For many years anatomists and anthropologists were
confined to measuring craniofacial dimensions using the skull of long dead individuals.
Although precise measurements were possible Craniometry has the disadvantage for
Cephalometry is concerned with measuring the head inclusive of soft tissues, be
it living or dead. However this procedure had its limitations owing to the inaccuracies
that resulted from having to measure skulls through varying thickness of soft tissues.
With the discovery of X rays by Roentgen in 1895, radiographic Cephalometry
came in to being. It was defined as the measurement of head from bony and soft tissue
land marks on the radiographic image (Krogman & Sassouni 1957). This approach
combines the advantages of Craniometry and anthropometry. The disadvantage is that it
produces two dimensional image of a three dimensional structure.
HISTORY PRIOR TO THE ADVENT OF RADIGRAPHY
History prior to the advent of radiography should begin with the mention of the attempts
of the scientists to classify the human physiques. In 500 BC, the Greek physician &
Father of medicine, Hippocrates, designated two physical types – habitus phithicus with a
long thin body subject to tuberculosis, & the habitus applecticus – a short thick individual
susceptible to vascular diseases & apoplexy. The search was continued by Aristotle (400
BC), Galen (200AD), & Rostan (1828), who was the first to include muscle mass as a
component of physique. Viola’s (1909) morphological index recognizes three
morphological types. Kretschmer (1921) adhered to the three Greek terms: the pyknic
(compact), asthenic (without strength), & athletic. Kretshmer also included dysplastic
physique which was taken up by Sheldon again in 1940.
The long historic thread extended into the twentieth century when Sheldon
introduced his method of somatotyping, based on three components of physiques, each
rated on a seven pt. scale& expressed as a three digit no. called as somatotype. It also
included a rating of dysplasia in the five regions of the body. “Dysplasia is literally bad
shape or form. In somatotyping it refers to disharmony or uneven distribution of a
component or components in diff. parts of the body,” acc. to Carter & Heath.
Morever their definition of a somatotype quantifies relative fatness or
endomorphy, relative musculoskeletal robustness, or mesomorphy,& relative linearity, or
ectomorphy. The somatotype then stands as a “quantitative overall appraisal of
bodyshape & composition, an anthropological identification tag & a useful descriptionof
human physique.” Heath & Carter also rigorously studied Sheldon’s instructions for
somatotyping & introduced modifications to method, designed to avoid some of the
limitation of Sheldon’s system.
Sheldon’s temperamental components, viscerotonia, somatotonia, & cerebrotonia,
convey behavioral traits commonly associated with physique. With a 7 pt. scale for each
somatotype component, there is a wide distribution in the dense midrange around the 4-4-
4 type ;a close relation between somatotype & temperament becomes tenuous.
Nonetheless common knowledge suffices to recognize dominant behavioral trait in many
instances, & that information can be revealing about the people in general. It may also
give some clues relating to the orthodontic treatment by providing an insight into the
character of the patients- their expectations concerning the treatment’s contribution to
their wellbeing, & even their understanding of & willingness to accept the discipline of
cooperation needed for successful conclusion of therapy.
MEASUREMENTS AND PROPORTIONS
Early history – The Canons
Portrayal of human form demands not only artistic talent & technical ability but a
disciplined & consistent style. To ensure these stipulations when images of royalty &
deity were commissioned & executed, the ancient Egyptians developed an intricate
quantitative system that defined the proportions of the human body. It became known as
the Canon. The theory of proportions acc. to Panofsky, is a
System of establishing the mathematical relations between the various members
of the living creature, in particular of the human being, in so far as these beings are
thought of as a subjects for artistic representation. The mathematical relation can be
expressed by the division of a whole as well as by the multiplication of the unit ; the
effort to determine them could be guided by the desire for beauty as well as interest in the
norms, or finally by the need for establishing a convention ; and above all, the
proportions can be investigated with reference to the object of representations well as
with reference to the representation of the object.
The proportions of the human body were determined with an ell measuring ruler,
established in 3000BC. Its length corresponded to the distance from the elbow to the
Initially the canons were enclosed in a grid system of equalized squares with 18
horizontal lines line 18 drawn through hairline. Later it was included in a grid system of
22 horizontal lines, line 21 drawn through the upper eyelid.
After the outline of the human figure was drafted on papyrus leaves the
iconographic norms or canon, served to insert the figure into a network of equal squares.
The image could be transferred to any required size by first drawing a coordinate system
to proper size ; into this system the image can then be drawn readily & accurately for
display in a tomb or on a wall. This procedure is still universally used to enlarge or
reduce any kind of illustration (MISE AU CARREAU).
The classical art of Greeks rejected the rigid Egyptian system for creating human
images. The Greeks needed the freedom to account for the shifting dimension of organic
movement, and the foreshortening of the upper part of a stature relative to the lower part.
Indian iconometry studied extensively by the Ruelius, was transmitted through
Sanskrit literature & extensively reviewed in Indian texts of architecture. The
proportional canons of that system were already detailed in older sources & did not
materially change with time. Face height was used as the module of both the sariputra &
alekhyalakshana proportional system, which closely reflected the natural relation of the
parts of the body to each other. The sariputra system , dated 1200 AD is known for the
sculptures honoring the God Buddha.
In the Byzantine empire, the rectangular grid of the canon was replaced by a
scheme of three concentric circles with nose length as the radius of drawing the two
RENAISSANCE TO THE TWENTIETH CENTURY
Fifteenth century saw the advent of specific measurements being made to
compare the features of different skulls and head. Leonardo da vinci (1452-1519 AD)
was probably one of the earliest people of note to apply the theory of head measurement
to good effect in practice.
He used a variety of lines related to specific structures in the head to assist in his
study of the human form (Fig-1). His drawings included a study of facial proportions in
natural head position. According to the notes the profile was divided in to seven parts by
eight horizontal lines. Sub division is made with vertical lines. In his study of horse &
horse men he used a scheme of facial measurement with in a grid system with five
horizontal and six vertical lines and the subject in natural head position (Fig-2). The
joining of the lower lip and chin and the tip of the jaw and the upper tip of the ear with
the temple forms a perfect square; and each face is half a head.
Albrecht Durer (1471-1528 AC) was a brilliant, unusually productive and
exuberant artist of great virtuosity. He published a treatise in 1528 on cranial
measurements which comprised “Vier Bucher von menschlischer Proportion” dealing
with the proper proportion of human form in the first two books, the proportions
according to mathematical rules in third book, the human figure in motion in the fourth
book. Durer’s four books mark a climax which the theory of proportions had never
reached before or was to reach ever after.
Using strictly geometrical methods he provided a proportionate analysis of the
leptoprosopic (long ) face and euryprosopic (broad) face in coordinate system, where the
horizontal and the vertical lines were drawn through the same land marks or facial
features (Fig-3). His drawings attest to continuous efforts to define variations in the facial
morphology. One of this is significant as the key to cephalometric analysis. In (Fig-4) the
difference between the retroclined and the proclined facial profile is shown by a change
of angle between the vertical and the horizontal axes of a rectangular coordinate system
to characterize the facial configuration of each subject.
The sixteenth century saw the first truly scientific attempt at cranial measurement
& the introduction by Spigel (1578-1625AC) of the “lineae cephalometricae”. Spigel’s
linear cephalometricae consisted of four lines: the facial, occipital, frontal, & sincipital
lines. He described these lines as follows:
• Facial: from the most inferior point of the chin to the most
superior point on the forehead.
• Occipital: from the crown of the head to the atlas.
• Frontal: from one temple to the other.
• Sincipital: from the lowest part of the ear, in the region of the
mastoid process, to the highest part of the sinciput, sinciput being
the anterior part of the head or skull from forehead to the crown.
According to him in a well proportioned skull, these lines should all be equal to
one another. In reporting this Aitken-Meiges writes “although these lines are evidently
not sufficient for the comparative ethnography, in ascending zoological scale, these lines
approximate just in proportion as the head measured approaches the human form. To
Spigel a skull was either well proportioned or it was not.
In 1699, a Cambridge physician, Edward Tyson (1650-1708 AD) under took
some measurements on the chimpanzee skull & proposed that there was an intermediate
animal between man and monkey. He described this animal as a form of ‘pigmy’ but this
pigmy was later shown to be another chimpanzee there by negating his findings.
In the eighteenth century most of the workers in the field of craniometry were
interested in relating intelligence to certain measurements. They not infrequently found
that their native race demonstrated a higher level of intelligence, according to their
measures than did others.
The Dutchman Pieter Camper (1722- 1789 AD) was credited with the
introduction of facial angle & for famous publication “Dissertation sur les varietes
naturelles de la physionomie” which appeared posthumously in 1791. The key to his
methodology was to orient crania in space on a horizontal from the middle of the porus
acusticus to a point below the nose. Camper’s horizontal became the reference line for
the angular measurements used to characterize evolutionary trends in studies of facial
morphology and aging.
The facial angle as he described it was formed by the intersection of a facial line
and a horizontal plane (Fig-5). The facial line was a line tangential to the most prominent
part of the frontal bone and to the slight convexity anterior to the upper teeth. The
horizontal plane passes through the lower part of the nasal aperture, backwards along the
line of the zygomatic arch, and through the centre of the external auditory meatus.
Camper’s facial angle was readily accepted as a standard measurement in
craniology. The terms prognathic and orthognathic introduced by Retzius are tied to
Camper’s illustrations of facial form in man and primates. As a result the angle between a
horizontal line and the line nasion – prosthion became the time-honored anthropological
method to determine the facial type. The term prognathism refers to the prominence of
the face, or jaws, relative to the fore head, and a straight facial profile became labeled as
Camper also provided a variety of other differences in facial form by comparing
the skull morphology of tailed simian, an orangutan, a young native African, and a
Kalmuck. Age changes in human physiognomy are also described by him. Frontal views
were also studied by Camper in a young orangutan, Kalmuck, native African, and the
face of Apollo Pythius. The most interesting proportional difference was the long face
height of native African.
The drawbacks of Camper’s facial angle were:
• It ignores the contribution made by he lower jaw to facial forms.
• He did not adhere strictly to his location of posterior reference point for the
• The direct comparison of skull of different ages was not possible because the
locating point might alter is position relevant to other bony structures with
Shortly after this Deschamps (1740- 1824 AC) introduced the cephalic triangle
made up of facial, occipital, & coronal angles. The facial angle was the lesser angle
formed by the intersection of a horizontal line that passed from the external auditory
meatus to the base of the nose, which crossed a profile line. This is similar to Camper’s
facial angle. Fortunately the use of external auditory meatus as a reference point enabled
a rough comparison to be made between different skulls.
The desire to learn how men differ from each other and from animals and why,
motivated several other craniologists like Doornick, Spix, Oken and many others to put
forward their individual methods of analyzing human and animal skulls.
In the same period as Camper, there was a French man; Daubenton (1716-1799
AC) was very concerned with the relative position of the foramen magnum in man and
lower animals. He made use of new angles, including the occipital angle to make
measurements. Although his measurements were not very reliable, a similar angle was
later used by another craniologist, Pierre Broca.
Daubentons occipital angle is formed by 2 lines (Fig-6): the first line passes
along the level of opening of the foramen magnum, from the inial edge of the foramen
along the surface of the occipital condyles & anteriorily for short distance. The second
line passes from the posterior margin of the foramen magnum to the tip of the nasal
spine. Broca’s occipital angle was formed by two different lines giving alternative angles,
originating from the posterior and anterior margins of the foramen magnum& passing
anteriorly through the junction of frontal and nasal bones (Fig-7). The magnitude of
occipital angle decreases as the habitual posture of the animal tends more towards
Daubenton’s interest in the position of the foramen magnum was shared by Sir
Charles Bell (1744 -1842 AC). According to him, since the head is movable on a pivot
joint, it must always be balanced. Therefore the Negro skull being heavier in front & thus
falling forward naturally is thrown backward to poise it and relieve the muscles which
support it behind.
This hypothesis was tested by a medical student, William Gibson (1788-1868
AC) in 1809 by placing in front of him Negroid &European skulls resting on their
occipital condyles. Contrary to expectation the European head fell forward and the
Negroid skull fell backward. Earlier Samuel Soemmering (1758-1826) had noted the
same point in 1785.
An antagonist of Camper, Johann Friedrich Blumenbach (1752- 1840 AC)
rejected the method of lines & angles as a test of national characteristics & proposed a
minute survey of the skull particularly the frontal and maxillary bones. In 1795 he
described a method of positioning the cranium to be measured in a standard reproducible
manner. His method was simple consisting of resting the skull on its base and looking
down vertically up on its vault. The points to be noted were the projection of the maxillae
anterior to the frontal arch, the directions of the jaws & cheek bones (outward, forward,
etc) & the proportional breadth or narrowness of the head. He completely rejected the
idea of viewing the skull in Norma lateralis.
Anders Retzius (1796-1860 AC) correlated the two schemes, i.e., of Camper and
Blumenbach, thereby providing a basis for the methods of craniology used today. He is
also credited with the introduction of cephalic index, the ratio of breadth to length of the
skull expressed as a percentage.
John Barclay (1758-1826 AC) proposed two new angles, the superior and the
inferior basifacial angles& for the first time, incorporated the mandible in to his
measurements. These angles were formed by the intersection of the basifacial lines with a
profile line. The superior basifacial line was drawn along the basilar surface of the
superior maxillary bone & the inferior basifacial line was drawn along the base of the
lower jaw. The superior basifacial angle was not dissimilar to Camper’s facial angle &
was measured by a custom made goniometer (supplied by Dr Leach.).
The nineteenth century produced three great men in the history of craniology:
Huxley, Broca& Topinard.
Thomas Huxley (1825-1895 AC) wrote in 1876 “the so called facial angle, in the
fact, does not simply express the development of the jaws in relation to the face, but is
the product of two factors, a facial& a cranial, which vary independently. The face
remaining the same, prognathism may be indefinitely increased, or diminished, by
rotation of the frontal region of the skull, backwards or forwards, upon the anterior end of
the basicranial axes”. He also introduced two new angles, the spheno maxillary and
spheno ethmoidal angles. He preferred the spheno maxillary angle to Camper’s angle
when comparing the degree of prognathism in different skulls. This angle is formed by
the two lines drawn from basion and prosthion to prosphenion. The other angle, spheno
ethmoidal tends to be less than 180° in man.
Broca (1824-1880 AC) who is the founder of the Paris Society of Anthropology
believed that the great variability of the cranial form constituted a principal difficulty for
the craniologist. He was the first craniologist to institute a precise and accurate technique
which could be used to compare crania so that it was made possible to discriminate
between the variations in racial types among human skulls. He introduced a base line
“plan alveolo- condylien” which passes through the alveolar point & tangential to the
inferior surfaces of the two occipital condyles. He also developed a craniostat, mainly
constructed of wood for positioning the skull (Fig-8).
It was generally accepted at this time that the angles were best determined on
projected drawings of the skull. Broca devised a simple method to trace the out line of the
skull on to a piece of paper by fixing the skull in the craniostat& positioning a drawing
board with paper attached to it parallel to the mid sagittal plane& a pencil held in a frame
perpendicular to the paper. The resultant tracing was equivalent to a tracing of the
peripheral as depicted on a lateral skull radiograph.
Paul Topinard (1830- 1912 AC) used a similar criniostat with some additional
modifications (Fig-9). Topinard wrote in 1890 “the craniometer substitutes the
mathematical data for the uncertain data founded on judgment and opinion. Moreover it
studies the skeleton of the ensemble, the cranium and the face separately and each of the
plates as well.
During nineteenth century the need for standardization of methods used in
craniometry became an important issue, and since then many bodies have met to better
define those points and planes in use. The most important meeting as far as the dental
profession is concerned was held in Frankfurt-am-Maine in August 1882. This was the
General Congress of the German Anthropological Society and it is to this
Congress that the Frankfurt Horizontal Plane owes its name.
century) translated the agreement and published it in the
Journal of Anthropological Institute 1885
Earlier in 1859 a horizontal plane following the zygomatic arches was suggested
by a Russian craniologist, Von Baer. Later the plane was defined more precisely as line
drawn from the centre of each auditory meatus to the lower point on the inferior margin
of each orbit by Von Ihering (1850-1930). The Frankfurt agreement modified Von
Ihesing’s definition so that the plane passes through the upper border of the bony meatus
vertically above their centres. However the reproducibility of this plane on an intact skull
is less than Broca’s condyloalveolar plane. Subsequent to the agreement the definition of
the horizontal plane has been altered so that it is now taken as passing through the right
and left porion &left orbitale. Thereby reducing the problems incurred by asymmetrical
Following the Frankfurt Agreement very little change of note has occurred in the
definition of points and planes. In 1914 Rudolph Martin (1864-1925) published the
“Lehrbuch der Anthropologie in Systematischer Darstellung mit besonderer
Berucksichtigung der anthropologischen Methodoen” & this is still renowned as a fine
reference book on physical anthropology.
In 1895, Professor William Conrad Roentgen made a remarkable contribution
to the field of science with the discovery of x-rays. On December 28 1895 he submitted a
paper “On A New Kind of Rays, A Preliminary Communication” to the Wurzburg
Physical Medical Society for publication in its journal.
Prof. Wilhem Koening & Dr. Otto Walkhoff simultaneously made the first
dental radiograph in 1896.
It was clear that the use of x-rays provided the means of obtaining a different
perspective on the arrangement and relation of bones thus expanding the horizons of
craniometry& cephalometry. The evolution of cephalometry in the twentieth century is
universally linked to Edward angle’s publication of his classification of malocclusion.
But the dogmatic inferences of the new school were criticized for failing to include
differential diagnosis of facial profile in patients with class iii& class ii malocclusion.
Van Loon was probability the first to introduce cepalometrics to orthodontics
when he applied anthropometric procedures in analyzing facial growth by making plaster
casts of face in to which he inserted oriented casts of the dentition. Hellman used
cephalometric techniques and described their value beginning with 1920s.
The first x- ray pictures of skull in the standard lateral view were taken by
A.J.Pacini & Carrera in 1922.Pacini received a research award from the American
Roentgen Ray Society for a thesis entitled “Roentgen Ray Anthropometry of the
Skull”. Pacini introduced a teleroentgenographic technique for standardized lateral head
radiography and thereby opened, what proved to become a tremendous advance in
cephalometry, as well as in measuring the growth and development of face. His method,
which was rather primitive, involved a large fixed distance from the x ray source to the
cassette. The head of the subject, placed adjacent to a standard holding the cassette, was
immobilized with a gauze bandage wrapped around both the face and the cassette after
the patient’s midsagittal plane was carefully oriented parallel to the cassette.
He identified the following anthropometric landmarks on the roentgenogram:
gonion, pogonion, nasion, and anterior nasal spine. He also located the centre of the sella
turcica and the external auditory meatus.he measured the gonion angle and the degree of
Atkinson in 1922 advocated the use of roentgenograms in locating the ‘key ridge’
and the soft tissue relations to the face and the jaws.
In 1923 Mc Cowen reported on profile roentgenograms that he used for
orthodontic purposes to visualize the relationship between the hard and soft tissues and to
note changes in profile which occur during treatment.
Simpson presented a method for obtaining profile roentgenograms in 1923 before
the American society of orthodontists.
In 1927 Ralph Waldron of Newark, N.J. made mention of measuring the gonion
angle from a roentgenogram taken at 90 to the facial profile. Waldron was the first to
construct a cephalometer, which differed little from those used today.
In 1928 Dewey and Riesner published an article, “A Radiographic Study of
Facial Deformity”. Dewey and Riesner immobilized the patients head in a head clamp
and placed the cassette against the patient’s face. They took profile roentgenograms by
aligning the eye- ear plane by a right angle leveling technique. They used a target
distance of three feet.
In 1931 the methodology of cephalometric radiography came to full function
when B. Holly Broadbent in USA and H. Hofrath in Germany simultaneously
published methods to obtain standardized head radiographs in the Angle Orthodontist (A
new X ray technique and its application to orthodontia) and in Fortschritte der
Orthodontie (Bedeutung der Rontgen fern und Abstands Aufnahme fur die
Diagnostik der kieferanomalien), respectively.
This development enabled orthodontists to capture the field of cephalometry from
the anatomists and anthropologists who had monopolized craniometric studies,
particularly in nineteenth century.
HOLLY B BROADBENT’S CONTRIBUTION
Broadbent’s interest in craniofacial growth began with his orthodontic education
under E.H. Angle in 1920. He continued to pursue that interest along with his orthodontic
practice, working with a leading anatomist J. Wingate Todd
The idea of diagnosing dental deformities by means of planes and angles was first
proposed in 1922 by Paul Simon of Germany in his book, “Fundamental Principles of
a Systematic Diagnosis of Dental Anomalies”. Although his “Law of the Canines”
was later disproved by Broadbent, his theories stimulated the latter to apply the principles
of craniometry to living subjects.
The uncertainty of locating land marks in the skull of the living child by
approaching through skin and soft tissues led hi to search for a means of recording
craniometric landmarks on the living child as accurately as done with a craniostat in
measuring the dead skull.
During 1920’s Broadbent refined the craniostat in to craniometer by the addition
of metric scales. That proved to be the first step in the evolution of craniostat in to a
radiographic cephalostat. It did not take him much longer to convert the direct measuring
instrument in to a radiographic craniometer.
Meanwhile the course of Broadbent’s orthodontic practice he corrected the
malocclusion of Charles Bingham Bolton, son of Chester and Francis P Bolton. His
discussions of facial growth with Congress woman Bolton led to the addition of Bolton
study of facial growth to the long list of Bolton philanthropies. As Charles grew to adult
hood this study became a major personal as well as financial commitment.
Cephalometrics was neither developed as a technique looking for an
application nor was it developed as a diagnostic tool. Broadbent’s single goal was the
study of craniofacial growth. The Broadbent technique for cephalometric radiography
was one of the tools that he developed for the implementation of that study.
The technique and apparatus perfected for the Bolton Fund study of the normal
developmental growth of the face, eliminated practically all of the technical difficulties
encountered in previous methods of recording dento-facial changes, and proved to be a
convenient as well as scientific method of measuring orthodontic procedures.
According to Broadbent the patient’s head was centered in the cephalostat with
the superior borders of the external auditory meatus resting on the upper parts the two ear
rods. The lowest point on the inferior bony border of the left orbit, indicated by the
orbital marker, was at the level of the upper parts of the ear rods. The nose clamp was
fixed at the root of the nose to support the upper part of the face. The focus film distance
was set a t 5 feet (152.4 cm) and the subject film distance could be measured to calculate
image magnification. With the two X ray tubes at right angles to each other in the same
horizontal plane, two images (lateral & postero anterior) could be simultaneously
produced. (A new x-ray technique and its application to orthodontia, By B. Holly
Broadbent D.D.S., Angle Orthodontist, April, 1931)
While Germany’s Hofrath’s technique differed from Broadbent’s in that the path
of the central ray was not fixed in relation to the head and no plan was suggested for
super positioning subsequent x-rays.
OTHER IMPORTANT CONTRIBUTIONS MADE BY BROADBENT.
In 1937, using serial records of twins; he showed how growth – or its lack – was
the greatest limiting factor in clinical success. In 1943 he stipulated that eruption of the
third molars had no ill effect on the denture, particularly the lower incisors.
In 1938, a group under Allan G. Brodie at the University of Illinois presented
material based on a cephalometric appraisal of orthodontic results:
1) The use of elastics causes a disturbance in the Bolton plane-occlusal plane angle;
2) Axial inclinations of orthodontically-moved teeth tend to return to their original
3) Bone changes during treatment are restricted to the alveolar process.
Brodie, in a landmark study (1941) used for his PhD in anatomy, corroborated
Broadbent’s contention that the growth pattern of the normal child’s face
develops in an orderly fashion downward and forward and that the pattern, once
attained at an early age, did not change.
Thompson and Brodie (1942) in a report on the rest position of the mandible,
1) The morphogenetic pattern of the head was established at a very early age and did
2) The presence or absence of teeth has little, if any, bearing on the form or the rest
position of the mandible; and
3) Vertical facial proportions are constant throughout life.
Margolis (1943) wrote on the relationship between the inclination of the lower
incisor and the incisor-mandibular plane angle and was the first to corroborate
Tweed’s clinical observation that, in normal occlusions, the lower incisors are 90°
to the mandibular basal bone.
In 1947, Wylie produced a method of assessing anteroposterior dysplasias, and,
that same year, Margolis contributed his maxillo-facial triangle.
(Lewis, A.B.: The impact of cephalometry on orthodontic concepts. Angle Orthodontist,
The major use of radiographic cephalometry is in characterizing the patient’s
dental and skeletal relationships. This led to the development of a number of
cephalometric analyses to compare a patient to his or her peers, using population
standards. William. B. Downs in 1948 developed the first cephalometric analysis. Its
significance was that it presented an objective method of portraying many factors
underlying malocclusion and there could be a variety of causes of malocclusion exclusive
to teeth. This was followed by other analyses by Cecil. C. Steiner (1953), C.H.Tweed
(1953) , R.M. Ricketts (1958), V.Sassouni (1969), H.D. Enlow (1969), J.R.
Jaraback(1970), & Alex Jacobson (1975) etc.
EVOLUTION OF CEPHALOMETRICS
The thoroughness of Broadbent’s approach to the design of the cephalometric
method is evident from the fact that the basic technique has survived almost unchanged
for over seventy years.
In about two decades times the instrumentation had evolved to a form more
suitable for the individual practitioner through the pioneering efforts of Margolis, Higley
The ears were established as the basis for orientation& fixation in the beam axis.
Frankfurt plane was adopted for horizontal orientation with nasion for stabilization. The
FH plane was chosen because this was approximate the natural head position (NHP). But
the FHP also had its drawbacks & these were:
1. Some individuals show a variation of their FH plane to the true horizontal to an
extent of ± 10°.
2. The landmarks to locate the FH plane, orbitale& porion, especially the latter are
difficult to identify on a cephalogram.
An alternative to overcome this problem was to use a functionally derived NHP.
According to Morrees &Kean, it was obtained by asking the subject to look at the image
of their eyes in the mirror located at eye level. A frame of reference was originally
intended as a reliable procedure for orienting facial profiles so that same orientation
could be established on different occasion by different investigators. Although the
functionally derived NHP was more accurate its reproducibility was less than FHP
(anatomic approximation of NHP). Lateral and posterio- anterior views perpendicular to
each other in the horizontal plane were specified for three dimensional analyses.
Bjork’s studies of facial prognathism illustrated the unreliability of intra cranial
reference lines in cephalograms (Some biological aspects of prognathism and occlusion
of teeth, Angle Orthodontist, 1951)
Kroagman and Sassouni (1957) conducted an exhaustive survey of
roentgenographic cephalometry in which the FH Plane coincided with the physiologic or
Sassouni made an attempt to standardize the orientation of cephalograms by
means of an optical plane advocated in 1862 by Broca, who stated that “when a man is
standing and when his visual axis is horizontal, he(his head) is I natural position.”
X-RAY SOURCE POSITION
The x-ray source is positioned 5 feet (152.4) from the subject’s midsagittal plane.
A change to 150 cm has been adopted by some as a conveniently round metric number,
but the difference is negligible. A major improvement in lateral cephalostats is the
capability of taking lateral& postero-antrior views with a single x-ray source instead of
FILM POSITION & ENLARGEMENT
The other significant change from the original technique is adjustability of film
position. The original cephalostat was based on the design of the anthropometric
craniometer &cassettes were attached to these mechanisms. The disadvantage of this very
efficient mechanical design is that it makes cassette position and resultant enlargement
depended on head size. Evaluation of serial changes by direct superimposition is made
unreliable by this variable enlargement.
The relative immunity of angular measurements to enlargement distortions led
many researchers to opt for angular over linear values whenever possible. Also newer
instruments have been developed that can over come this drawback of variable
enlargement by providing independent adjustments for head holding mechanisms and
POSTERO-ANTERIOR (FRONTAL) CEPHALOMETRY
Since the introduction of a standardized method for obtaining skull radiographs,
cephalometrics has become one of the major diagnostic tools in orthodontics. The
posterior anterior cephalogram contains diagnostic information not readily available from
other sources. This information allows the practitioner to evaluate the width and
angulation of the dental arches in relation to their osseous bases in the transverse plane;
evaluate the width and transverse positions of the maxilla and mandible; evaluate the
relative vertical dimensions of bilateral osseous and dental structures; assess nasal cavity
width; and analyze vertical and/or transverse facial asymmetries.
Malocclusions &dentofacial deformities constitute three dimensional conditions
or pathologies. Although all orthodontic patients deserve an equally comprehensive three
dimensional diagnostic examinations, assessment of postero- anterior cephalometric
views are of particular importance in cases of:
1. Dento alveolar & facial asymmetries
2. Dental & skeletal cross bites.
3. Functional mandibular displacements
The same equipment that is used for the lateral cephalometric projections is
utilized. The initial unit described by Broadbent consisted of a set up in which two X ray
sources with two cassettes were simultaneously used, so that lateral and frontal
cephalograms were taken at the same time. Although precise three dimensional
evaluations are possible using this technique, it has now been almost abandoned since it
requires rather large equipment with two x ray sources.
Modern equipment uses one x-ray source. Therefore following lateral
cephalometric registration, the patient must be repositioned if a postero anterior
cephalogram has to be produced. A head holder or cephalostat that can be rotated 90° is
used, so that the central X ray beam penetrates the skull of the patient in a postero
anterior direction and bisects the transmeatal axis perpendicularly. Maintaining the
identical horizontal orientation from lateral to the postero- anterior projection is critical
when comparative measurements are made on each other. (Moyers et al, 1988)
In using natural head position for postero anterior cephalometric registrations,
some practical problems are encountered. The patient’s head is facing the cassette; which
makes it difficult for the patient to look in to a mirror to register natural head position
(Solow &Tallgren, (1977). Furthermore, space problems make it impossible to place a
nose piece in front of nasion to establish support in a vertical plane.
For better evaluation of patients with craniofacial anomalies that require special
attention to the upper face, the patient head should be positioned with the tip of the nose
and forehead lightly touching the cassette holder. (Chierci, 1981)
In cases of suspected significant mandibular displacement, the PA cephalogram
should be taken with the mouth of the patient slightly open in order to differentiate
between functional mandibular displacements & dentoskeletal facial asymmetry (Faber,
1985). As far as exposure conditions and considerations are considered, more exposure is
needed for PAcephalograms than lateral views (Enlow, 1982)
CEPHALOMETRIC LAND MARKS
Cephalometric landmarks are readily recognizable points on a cephalometric
radiograph or tracing, representing certain hard or soft tissue anatomical structures
(anatomical landmarks) or intersections of lines (constructed landmarks).landmarks
are used as reference points for the construction of various cephalometric lines or planes
and for subsequent numerical determination of cephalometric measurement.
Measure points and land marks used in anthropometrics were formulated at a
series of international congress on “Prehistoric Anthropology and Archeology.” three
of the more important ones were held at Frankfort (1882), Monaco (1906), and Geneva
(1912). The agreements reached at Monaco and Geneva state that “A land mark in
anthropometry is as near as possible a definite point from or to which to measure.”
Landmarks show a fairly definite range of normal variation or oscillation about
mean. It is important for the orthodontist to determine whether facial dimensions and
relationship of facial components fall with in the range of normal variation or whether the
deviations are to be classified as abnormalities.
REQUIREMENTS OF LANDMARKS AND MEASURE POINTS
1. Landmarks should be easily seen on the roentgenogram, be uniform in out line,
and easily reproducible.
2. Lines and planes should have significant relationship to the vectors of growth of
3. Landmarks should permit valid quantitative measurements of lines and angles
projected from them.
4. Measure points and measurements should have significant relation to the
5. Measurements should be amenable to statistical analyses but should preferably
not require extensive specialized training, in statistical methods.
Garn (1961) pointed out that there are no ‘fixed points’ in the skull of living
person. Variability of the landmarks depends on age, sex, maturation rate, ethnic
background, and other factors.
Following is a list of the most commonly used cephalometric landmarks. In these
definitions, the following convention is used: midsagittal identifies landmarks lying on
the midsagittal plane, unilateral identifies land marks corresponding to unilateral
structures and bilateral applies to landmarks corresponding to bilateral structures.
HARD TISSUE LANDMARKS
• A-point (Point A, Subspinale, ss) : the deepest point (most posterior) midline
point on the curvature between the ANS and prosthioin
• Anterior nasal spine (ANS): the tip of the bony anterior nasal spine at the
inferior margin of the piriform aperture in the midsagittal plane.
• Articulare (Ar) : a constructed point representing the intersection of three
radiographic images: the inferior surface of the cranial base and the posterior out
line of the ascending rami or mandibular condyles
• B-point (Point B, Supramentale, sm): the deepest (most posterior) midline point
on the bony curvature of the anterior mandible, between infradenale and
• Basion (Ba): the most anterior inferior point on the margin of the foramen
magnum in the midsagittal plane.
• Bolton (Bo) : the highest points on the outlines of the retrocondylar fossae on the
occipital bone, approximating the centre of the foramen magnum
• Condylion (Co) : the most superior point on the head of the mandibular condyle
• Glabella (G): the most prominent point of the anterior contour of the frontal bone
in the midsagittal plane.
• Gnathion (Gn) : the most anterior inferior point on the bony chin in the
• Gonion (Go): the most posterior inferior point on the outline of the angle of the
• Incision inferius (Ii) : the incisal tip of the most labially placed mandibular
• Incision superius (Is) : the incisal tip of the most labially placed maxillary
• Infradentale (Id, Inferior prosthion) : the most superior anterior point on the
mandibular alveolar process between the central incisors
• Menton (Me): the most inferior point of the mandibular symphysis in the
• Nasion (N,Na) : the intersection of the internasal and frontonasal sutures in the
• Opisthion (Op) : the most posterior inferior point on the margin of the foramen
magnum in the midsagittal plane
• Orbitale (Or) : the lowest point on the inferior orbital margin
• Pogonion (pog, P, Pg) : the most anterior point on the contour of the bony chin in
the midsagittal plane
• Porion (Po): the most superior point of the outline of the external auditory
meatus (anatomic porion). When the anatomic porion cannot be located readily
the superior most point of the image of the ear rods (machine porion) sometimes
is used instead.
• Posterior nasal spine (PNS) : the most posterior point on the bony hard palate in
the midsagittal plane, the meeting point between the inferior and the superior
surfaces of the bony hard palate at its posterior aspect
• Prosthion (Pr, Superior prosthion, Supradentale): the most inferior anterior
point on the maxillary alveolar process between the central incisors.
• Pterygomaxillary fissure (PTM, Pterygomaxillare): a bilateral inverted tear
drop shaped radiolucency whose anterior border represents the posterior surfaces
of the tuberosities of the maxilla. The landmark is taken at the most inferior point
of the fissure, where the anterior and the posterior outline of the inverted teardrop
merge with each other.
• R- Point (Registration point): a cephalometric reference point for registration of
• Sella (S): the geometric centre of the pituitary fossa (sella turcica), determined by
inspection – a constructed point in the midsagittal plane.
SOFT TISSUE LANDMARKS
• Cervical point (C): the innermost point between the submental area and the neck
in the midsagittal plane. Located at the intersection of lines drawn tangent to the
neck and submental areas.
• Inferior labial sulcus (Ils): the point of the greatest concavity on the contour of
the lower lip between the labrale inferius and menton in the midsagittal plane.
• Labrale inferior (Li): the point denoting the vermillion border of the lower lip in
the midsagittal plane.
• Labrale superior (Ls): the point denoting the vermillion border of the upper lip
in the midsagittal plane.
• Pronasale (Pn): the most prominent point of the tip of the nose, in the midsagittal
• Soft tissue glabella (G’): the most prominent point of soft tissue drape of the fore
head in the midsagittal plane.
• Soft tissue menton (Me’): the most inferior point of the soft tissue chin in the
• Soft tissue nasion (N’, Na’): the deepest point of the concavity between the
forehead and the soft tissue contour of the nose in the midsagittal plane.
• Soft tissue pogonion (Pg’, Pog’): the most prominent point on the soft tissue
contour of the chin in the midsagittal plane.
• Stomion (St): the most anterior point of contact between the upper and lower lip
in the midsagittal plane. When the lips are apart at rest, a superior and an inferior
stomion point can be distinguished.
• Stomion inferius (Sti): the highest midline point of the lower lip.
• Stomin superius (Sts) : the lowest midline point of the upper lip
• Subnasale (Sn): the point in the midsagittal plane where the base of the
columella of the nose meets the upper lip.
• Superior labial sulcus (Sls): the point of greatest concavity on the contour of the
upper lip between subnasale and labrale superius in the midsagittal plane.
• Trichion (Tr): an anthropometric landmark, defined as the demarcation point of
the hair line in the midline of the forehead.
POSTERO- ANTEROIR CEPHALOGRAMS
A. BILATERAL SKELETAL LANDMARKS
• Greater Wing Superior Orbit (GWSO) - the intersection of the superior border
of the greater wing of the sphenoid bone and lateral orbital margin.
• Greater Wing Inferior Orbit (GWI0) - the intersection of the inferior border of
the greater wing of the sphenoid bone and the lateral orbital margin.
• Lesser Wing Orbit (LWO) - the intersection of the superior border of the lesser
wing of the sphenoid bone and medial aspect of the orbital margin.
• Orbitale (O) - the midpoint of the inferior orbital margin.
• Lateral Orbit (LO) - the midpoint of the lateral orbital margin.
• Medial Orbit (MO) - the midpoint of the medial orbital margin.
• Superior Orbit (SO) - the midpoint of the superior orbital margin.
• Zygomatic Frontal (ZF) - the intersection of the zygomaticofrontal suture and
the lateral orbital margin.
• Zygomatic (Z) - the most lateral aspect of the zygomatic arch.
• Foramen Rotundum (FR) - the center of foramen rotundum.
• Condyle Superior (CS) - the most superior aspect of the condyle.
• Center Condyle (CC) - the center of the condylar head of the condyle.
• Mastoid Process (MP) - the most inferior point on the mastoid process.
• Malar (M) - the deepest point on the curvature of the malar process of the
• Nasal Cavity (NC) - the most lateral point on the nasal cavity.
• Mandible/Occiput (MBO) - the intersection of the mandibular ramus and the
base of the occiput.
• Gonion (G) - the midpoint on the curvature at the angle of the mandible (gonion).
• Antegonial (AG) - the deepest point on the curvature of the antegonial notch.
B. MIDLINE SKELETAL LANDMARKS
• Crista Galli (CG) - the geometric center of the crista galli.
• Sella Turcica (ST) - the most inferior point on the floor of sella turcica.
• Nasal Septum (NSM) - the approximated midpoint on the nasal septum between
crista galli and the anterior nasal spine.
• Anterior Nasal Spine (ANS) - the center of the intersection of the nasal septum
and the palate.
• Incisor Point (IPU) - the crest of the alveolus between the maxillary central
• Incisor Point (IPL) - the crest of the alveolus between the mandibular central
• Genial Tubercles (GT) - the center of the genial tubercles of the mandible.
• Menton (ME) - the midpoint on the inferior border of the mental protuberance.
C. BILATERAL DENTAL LANDMARKS
• Maxillary Cuspid (MX3) - the incisal tip of the maxillary cuspid.
• Maxillary Molar (MX6) - the midpoint on the buccal surface of the maxillary
• Mandibular Cuspid (MD3) - the incisal tip of the mandibular cuspid.
• Mandibular Molar (MD6) - the midpoint on the buccal surface of the
mandibular first molar.
IDENTIFICATION AND REPRODUCIBILITY OF CEPHALOMETRIC
It is essential to evaluate the validity of information obtained from the lateral head
film. Cephalometric measurements on radiographic images are subject to errors that may
be caused by radiographic projection errors with in the measuring system & errors in
Landmark identification errors are considered as the major source of
cephalometric error. Many factors are involved uncertainty. They are:
• Density & sharpness of the image
• Anatomic complexity & superimposition of hard and soft tissues
• Observer’s experience in locating a landmark and defining the location of the
A Meta analysis was carried out by B. Tipkova, P. Major, N. Prasad&B. Hebbe in
To determine the reproducibility of some commonly used 15 landmarks. Meta
analysis is a quantitative review technique described as the statistical analysis of a large
collection of results from individual studies for the purpose of integrated finding.
The 15 landmarks were N, S,Or, Ba, P, ANS, PNA, Pt. A, Ptm, Go, Co, Ar, Pog,
Me, Pt.B. It was concluded from the study that some landmarks are more reproducible in
a horizontal direction and others in a vertical direction. B, A, Ptm,Go, & S, exhibited
acceptable levels of accuracy along the horizontal axis. A, S, Ptm exhibited acceptable
levels of along the vertical axis as well.
LANDMARK IDENTIFICATION ERROR IN POSTERIOR ANTERIOR
Paul W. Major, Donald E. Johnson and Karen L. Hesse conducted a study
which was designed to quantify the intraexaminer and interexaminer reliability of 52
commonly used posterior anterior cephalometric landmarks. The horizontal and vertical
identification errors were determined for a sample of 33 skulls and 25 patients. The
results show that there is a considerable range in the magnitude of error with different
horizontal and vertical values.
Interexaminer landmark identification error was significantly larger than
intraexaminer error for many landmarks. The identification error was different for the
skull sample compared to the patient sample for a number of landmarks. The relevance of
knowing the identification error for each landmark being considered in a particular
application was discussed.
Regardless of the clinical or research application, it is critical to know the
reliability of the reference landmarks. Baumrind and Frantz point out that there are two
general classes of error associated with cephalometric measurements. The first class of
errors is “projection” errors which arise from the geometry of the radiographic setup.
The fact that the x-ray beam originates from a source which has a finite size leads
to a penumbra effect or optical blurring. The x-ray beam diverges as it moves away from
the source, which results in an overall magnification of the object being radiographed and
a radial displacement of all points which are not on the principal axis (central ray). The
radiographic image is distorted as points closer to the film are magnified less than points
farther from the film.
The second general class of landmark errors may be termed “errors of
identification,” and arise due to uncertainty involved in locating specific anatomic
landmarks on the radiograph. The precision with which any landmark may be identified
depends on a number of factors.
Landmarks lying on a sharp curve or at the intersection of two curves are
generally easier to identify than points located on flat or broad curves.
Points located in areas of high contrast are easier to identify than points located in areas
of low contrast. Superimposition of other structures, including soft tissue over the area of
the landmark in question, reduces the ease of identification.
Precise written definitions describing the landmark reduces the chance of
interpretation error. Operator experience is an important factor since increased
knowledge of anatomy and familiarity with the radiographic appearance of the subject
reduces interpretive errors.
A literature review concerning the reliability of landmark identification in
posterior anterior cephalometrics revealed only one article, by El-Mangoury et al.,
which determined the horizontal, vertical and radial variability of 13 landmarks.
They found that each landmark had its own characteristic noncircular envelope of
error, and that the variability is different in the horizontal and vertical directions.
Unfortunately, the majority of posterior anterior cephalometric analyses use landmarks
whose identification error has not been independently reported.
Broadbent did not present the profession with a premature infant in the need of
artificial; life support and careful nurture. He gave us a gangling but vigorous adolescent
ready to enter the work force.
Clinical orthodontics is yet to fully utilize Broadbent’s contribution. He gave us a
three dimensional analysis, but orthodontics has remained preoccupied with the lateral
view. The lateral view is easy to work with and the patient is also much more
recognizable than in the frontal (P-A) view, especially with soft tissue enhancement. But
it is not enough.
We treat in three dimensions and the width dimensions that are visualized on the
frontal view are crucial in many cases. In these days of increasing awareness of the
contribution of muscular and respiratory function, we can no more afford to continue to
close our eyes to the information in the frontal view than we could afford to ignore the
lateral view up to now.
1. Craniometry and Cephalometry: A History Prior to the Advent of
Radiography – Laetitia. M. Finlay ; Angle Orthodontist 1980
2. Fifty Years of Cephalometric Radiography – Editorial ; Angle Orthodontist
3. A New X Ray Technique and its Application in Orthodontia – B. Holly
Broadbent ; Angle Orthodontist 1931
4. Radiographic cephalometry – Alexander Jacobson
5. Practice of Orthodontics – J.A. Salzmann
6. Orthodontic Cephalometry – Athanasios. E. Athanasiou
7. Oral Radiology – Paul .W. Goaz, Stuart. C. White
8. Cephalometric Radiography – Thomas Rakosi
9. Glossary of Orthodontic terms – John Daskalogiannakis
10. Contemporary Orthodontics – William R. Proffit
11. Lewis, A.B.: The impact of cephalometry on orthodontic concepts. Angle
12. Some biological aspects of prognathism and occlusion of teeth, Angle
13. Cephalometric Landmarks Identification & Reproducibility – A Meta analysis
– American journal of orthodontics 1997
14. Landmark identification error in posterior anterior cephalometrics Paul W.
Major, Donald E. Johnson, Karen L. Hesse- Angle Orthodontist, 1994
15. Résumé of the workshop and limitations of the technique – Salzmann, AJO-