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K. Miller - Forensic Science Communications - January 2004

K. Miller - Forensic Science Communications - January 2004

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January 2004 - Volume 6 - Number 1

Research and Technology

A Survey of Tissue-Depth Landmarks for Facial Approximation

Rebecca E. Brown
Computer Scientist

Timothy P. Kelliher
Computer Scientist

Peter H. Tu
Computer Scientist

Wesley D. Turner
Computer Scientist
General Electric Global Research
Imaging Technologies
Niskayuna, New York

Michael A. Taister
Visual Information Specialist
Investigative and Prosecutive Graphics Unit

Kevin W. P. Miller
Research Biologist
Counterterrorism and Forensic Science Research Unit
Federal Bureau of Investigation
Quantico, Virginia

Abstract | Introduction | Tissue-Depth Landmarks
Frontal Bone | Temporal Bone | Zygomatic Bone | Nasal Bone | Maxilla | Mandible
Occipital and Parietal Bones | Discussion | References

Abstract

A common method of three-dimensional forensic facial reconstruction from human remains involves building an approximation of a face directly on the questioned skull using clay. In this method forensic artists place tissue-depth markers at predetermined landmarks distributed around the skull. These markers guide the application of clay to the skull in order to form the final approximation of soft tissue-depth. Although locations and tissue-depth data for many landmarks are published in tissue-depth tables, a standard set of tissue-depth landmarks does not exist. Furthermore, even where different tables refer to the same landmark, there often is no agreed upon definition of the individual landmarks. This leaves the choice of tissue-depth table and the interpretation of the landmarks in the table to the subjective application of the forensic artist. The purpose of this paper is to present the tissue-depth landmarks currently available to forensic artists in order to highlight the need for standardizing the set of landmarks and the landmark definitions used in three-dimensional forensic facial reconstruction.

Introduction

Forensic three-dimensional facial approximation is the process of recreating the countenance of a person based on an unknown or questioned skull. Whereas a number of techniques exist, those in widest use by the forensic community in the United States begin by applying a sparse set of tissue-depth markers at defined landmarks on the skull (Taylor 2001). These markers are then used to guide the application of the clay used to approximate the face. Although forensic anthropologists have collected soft tissue measurements since the late 19th century, consensus on a set of standard landmarks that are used to guide an accurate forensic facial approximation has yet to emerge. Rather, it is largely up to the individual forensic artist to choose tissue depths from any one of a number of tables based on the attributes of a particular questioned skull. The forensic artist then must place the tissue-depth markers on the skull in a manner that approximates the landmark as originally described. Leaving the choice of landmarks and the interpretation of landmark placement up to the forensic artist introduces subjectivity into an approximation. Collecting and categorizing the landmarks included in tissue-depth tables highlight the inconsistencies in current forensic practice that contribute to this subjectivity, and the need for standardizing tissue-depth tables used in forensic facial approximation.

Tissue-Depth Landmarks

The following sections catalog the landmarks defined in the surveyed tissue-depth tables used in forensic facial approximation (Table 1) by the bone in which they are most often located. Each section consists of a table grouping the landmarks by approximate location (Tables 2-9), an image highlighting the approximate locations of the landmarks on the bone (Figures 1-7), and text describing some of the apparent similarities and discontinuities between the tissue-depth landmarks and the methods of measuring the soft tissue depths. In the cases when no description or reference has been given in the text accompanying a tissue-depth table, the description in the table is cross-referenced to a common definition of the landmark (Table 10) given by Bass (1995), Stedman (2000), White (2000), or Taylor (2001). The lack of standards becomes evident from observing the number of landmarks in the tables with multiple, and often conflicting, definitions.

Landmarks on the Frontal Bone

The landmarks on the frontal bone (Table 2, Figure 1) describe the soft tissue depths of the forehead and the upper border of the eye, or orbit. All of the surveyed researchers defined landmarks at the glabella (Landmark 2.6). As shown in Table 2, the exact definition of this point varies from author to author. The tissue-depth tables also each contain a point above the orbit (Landmark 2.8). Sometimes this landmark is defined with respect to the superciliary arch or to the supraorbital ridge. Other times this point is defined with reference to the eyebrow, a soft tissue feature itself, which is not present during a forensic facial approximation. Lebedinskaya et al. (1993) portrayed this landmark as being closer to the midline of the face than the rest of the authors.

The other landmarks on the frontal bone add definition to the forehead. Helmer (1984) added six additional points around the forehead, whereas Manhein et al. (2000) did not add any. Rhine and Campbell (1980) measured separate tissue depths at the supraglabella and the frontal eminence, although, according to Taylor (2001), the current standard practice among forensic artists is to use only the tissue depth at the supraglabella to develop the forehead.

Forensic artists rarely place landmarks above the hairline, because they are covered with a wig or clay representing hair. For this reason, common anthropological landmarks such as vertex and bregma, although included in this discussion for completeness, are not used. Defining landmarks in terms of the soft tissues of the face, which are not available to the forensic artist during the forensic facial approximation, is a recurring issue throughout the tables. In the case of the trichion, a cephalometric point dependent on the hairline, later tissue-depth tables have replaced it with the craniometric landmark metopion or supraglabella. The definitions by Aulsebrook et al. (1996) of supraorbital (US3) and frontal (US1) landmarks, however, depend upon the location of the pupil of the eye. As with the eyebrow, this is not available to a forensic artist when completing a forensic facial approximation. It can be assumed that the numerous references to the eyebrow throughout the table can be directly substituted with the superciliary arch when building a forensic facial approximation.

Landmarks on the Temporal Bone

The temporal bone contains the bony structures around the ear, part of the cheek, and the temple region. Only three landmarks for forensic facial reconstruction, one for each of these regions, are defined on this bone (Table 3, Figure 2). The most commonly defined landmark on the temporal bone is the zygion, also named the lateral or midzygomatic. Since it is defined as the most lateral point, or the highest point, of the zygomatic arch, the location of the zygion in relation to the other bony landmarks is highly variable, dependent on the bone structure of the individual in question. Of the tables surveyed, the majority listed the tissue depth at a single landmark located either on the temporal fossa or near the bony ear, highlighting the existing lack of standardization in the set of landmarks available to the forensic artist.

Landmarks on the Zygomatic Bone

The zygomatic bone, commonly known as the cheekbone, consists of much of the cheek along with the lower and the outer borders of the orbit (Table 4, Figure 3). Two of the landmarks define the borders of the eye orbit, although twice as many researchers defined the landmark on the lower border as on the outside edge. As on the frontal bone, those landmarks around the eye socket are often defined in terms of the soft tissue of the eye. Further research is needed to determine if such references affect the accuracy of a reconstruction in such a way to change the recognition rate. The researchers surveyed do not agree on the name or a consistent definition of the one landmark located in the cheek region. Rhine and Campbell (1980), Lebedinskaya et al. (1993), and Manhein et al. (2000) refer to it as the lateral orbit, the malare, and the zygomatic, respectively.

Landmarks on the Nasal Bone

The nasal bone (Table 5, Figure 4) has the fewest landmarks for forensic facial approximation and perhaps for this reason the researchers for the most part agree on those locations. Of the researchers surveyed, all placed a landmark at the root of the nasal bone (nasion) and all except His (1895) placed another at the tip (rhinion). His instead placed a second landmark along the midline of the nasal bone.

Landmarks on the Maxilla Bone

The maxilla (Table 6, Figure 5) encompasses many areas of the face, including the sides of the nasal opening, the lower cheek, and the upper half of the mouth. The researchers surveyed did not agree on the number or the locations of the landmarks on this bone. While early researchers concentrated on two landmarks between the nose and the mouth (subnasale and philtrum), later researchers added greater definition through landmarks around both the nose and the upper mouth. Aulsebrook et al. (1996) defined 16 landmarks on the maxilla; many of them only slight variations of each other and differing primarily based on the angle the measurement was taken from the skull. One of these sets, at the nose tip (LR6, LR7, LR8), is dependent on the soft tissue of the known face being measured and is impossible to recreate on a questioned skull. Similarly, the nostril measurement of Manhein et al. (2000) depends on the existence of a complete nose to place accurately.

Overall, the landmarks located on the nasal bone and around the nasal opening on the maxilla give little information to the forensic artist on the structure of the soft tissues of the nose. There is insufficient research to conclude that the shape and the size of the nose can be determined solely based on the bone structure of the skull. Forensic artists typically use their artistic skill and rough heuristics to guide forensic facial approximations in this area. In addition, forensic artists feel that the tissue-depth measurements at the inferior malar (Landmark 6.5) and the supra-M2 (Landmark 6.6), along with the sub-M2 (Landmark 7.2), are too shallow to provide accurate guidance in a forensic facial approximation. Instead, they build the soft tissues of the cheek and the jaw directly based on the skull of the individual in question, taking into account the musculature and facial expression (Taylor 2001).

Landmarks on the Mandible Bone

The mandible (Table 7, Figure 6), covering the lower mouth, the chin, and the lower jaw, not only contains the greatest number of defined landmarks, but it is also the region with the most landmarks common among the researchers. Although they disagree on its name, each placed a landmark at the deepest point along the midline between the lower lip and the chin. They also located landmarks at the pogonion, or mental eminence, and under the chin. George (1987, 1993) defined two points under the chin, the gnathion and the menton. The other researchers surveyed measured at only one landmark, and it is often unclear which landmark they are referring to based on the definitions in the text, or lack thereof. Most of the researchers placed a landmark along the edge of the jaw, although they defined different locations for this landmark. Over half were defined in relation to the masseter muscle or its insertion point on the lower jaw, making it difficult to accurately locate without sufficient training in anatomy.

Landmarks on the Occipital and Parietal Bones

The soft tissue covering the occipital (Table 8, Figure 7) and parietal bones (Table 9, Figure 7) do not directly affect a facial approximation. Suzuki (1948), Helmer (1984), and George (1993), however, have included landmarks from these bones in their respective tables, and the landmarks are included here to provide a complete list of the landmarks on the skull at which soft tissue depths have been measured.

Discussion

A key element of using the tissue-depth tables to guide a facial approximation is the dependence on a particular published set of average tissue depths. Whereas the errors in obtaining such measurements have decreased through the use of newer and more rigorous methods, the issues inherent in the use of the tissue-depth tables have instead increased in complexity with each new table published.

The primary issue concerns the need for standardizing the landmarks of the tissue-depth table used in the forensic reconstruction of facial features from human remains. As shown above, the researchers surveyed choose their own set of landmarks at which to measure the tissue depths. As such, few of the tissue-depth tables surveyed list a standard set of landmarks that would provide an accurate guide for the forensic artist. The five landmarks common to all of the tables, the glabella, the nasion, the chin-lip groove, the pogonion, and the gnathion, are all located along the midline of the face. One possible cause of the lack of common landmarks is the difficulty of accurately locating well-defined craniometric landmarks through the soft tissues of a cadaver or, conversely, the difficulty of locating landmarks on the questioned skull that have been defined in terms of the soft tissue. Other causes could include the selective choosing of landmarks used in previously published tissue-depth tables and the selection of landmarks based on the personal preference of the researcher. Whatever the reason, the lack of a standardized set of landmarks to guide the forensic artist makes the objective evaluation of a forensic facial approximation difficult.

A second issue highlighted by the need for standardization and by the above list of landmarks is the lack of a concrete set of definitions. Half of the tissue-depth tables surveyed neither include nor reference definitions for all of the landmarks listed. The lack of a definition is most apparent when the landmark is not a craniometric landmark but describes a region of the face, such as fossa canina (Lebedinskaya et al. 1993) or is a general term that cannot be completely defined by a dictionary or textbook, such as end of nasal (Rhine and Campbell 1980). Other nonconformities occur when two tissue-depth tables claim to measure at the same location on the skull but have definitions different from each other and/or a so-called common knowledge definition, such as the root of the zygoma (Aulsebrook et al. 1996; Manhein et al. 2000) and the gnathion and the menton (all). The forensic artist is left to assume that an undefined landmark is defined by the common-knowledge definition, which induces subjectivity into the use of the tissue-depth tables and, therefore, the facial approximation. Even when the definition of a landmark is given or is common knowledge, the definition may not give all the necessary information for the forensic artist to place the landmark correctly during a forensic facial approximation. With the exception of George (1993) and Aulsebrook et al. (1996), the definitions do not include information regarding the angle of measurement of the landmarks in relation to the skull. Without this, the forensic artist cannot reliably reproduce the placement of the landmarks as intended by the forensic anthropologist.

Due to the lack of standardization in the landmarks and their definitions used in the tissue-depth tables, the forensic artist is given the leeway to not only choose the table of preference but also the leeway to interpret the location of the landmarks. For example, Taylor (2001) suggests that five of the landmarks defined by Rhine et al. (Rhine and Campbell 1980; Rhine and Moore 1982) are not useful to a forensic artist and should, therefore, be ignored during a three-dimensional forensic facial approximation. This induces a level of subjectivity into the use of the landmarks and the facial approximation itself. Given a questioned skull and a set of anthropological data about the individual in question (sex, race, age, height, weight, stature), it is not possible for a forensic artist to develop an objective and repeatable forensic facial approximation. The first solution to correct this issue is to develop a standard set of landmarks and definitions that could guide a forensic artist to repeatedly and reliably create a recognizable facial approximation. Further solutions could include developing an automatic method for placing the landmarks on the skull to rely less on the interpretation of the accurate location by the forensic artist and perhaps introducing a new objective method of facial approximation that does not depend on the subjective choices of the forensic artists.

References

Aulsebrook, W. A., Becker, P. J., and Iscan, M. Y. Facial soft tissue thickness in the adult male Zulu, Forensic Science International (1996) 79:83-102.

Bass, W. M. Human Osteology: A Laboratory and Field Manual. Missouri Archaeological Society, 1995.

Campbell, C. E. A problem in human variation: The facial tissue thicknesses of Caucasoids, Negroids, and Mongoloids. Doctoral thesis, University of New Mexico, Albuquerque, New Mexico, 1981.

George, R. M. Anatomical and artistic guidelines for forensic facial reconstruction. In: Forensic Analysis of the Skull. M. Y. Iscan and R. P. Helmer, eds. Wiley-Liss, New York, 1993, pp. 215-227.

George, R. M. The lateral craniographic method of facial reconstruction, Journal of Forensic Sciences (1987) 32:1305-1330.

Helmer, R. Schädelidentifizierung durch Elektronische Bildmischung. Kriminalstik-Verlag, Heidelberg, 1984.

His, W. Anatomische Forschungen über Johann Sebastian Bach's Gebeine und Antlitz nebst Bemerkungen über Dessen Bilder. In: Abhandlungen der Mathematisch-Physischen classe Der Königlich Sächsischen Gesellschaft der Wissenschaften. Bei S. Hirzel, Leipzig, 1895, pp. 379-420.

Kollmann, J. and Büchly, W. Die persistenz der rassen und die reconstruction der physiognomie prähistorischer Schädel, Archiv fur Anthropologie (1898) 25:329-359.

Lebedinskaya, G. V., Balueva, T. S., and Veselovskaya, E. V. Principles of facial reconstruction. In: Forensic Analysis of the Skull. M. Y. Iscan and R. P. Helmer, eds. Wiley-Liss, New York, 1993, pp. 183-98.

Manhein, M. H., Listi, G. A., Barsley, R. E., Musselman, R., Barrow, N. E., and Ubelaker, D. In vivo facial tissue-depth measurements for children and adults, Journal of Forensic Sciences (2000) 45:48-60.

Phillips, V. M. and Smuts, N. A. Facial reconstruction: Utilization of computerized tomography to measure facial tissue thickness in a mixed racial population, Forensic Science International (1996) 83:51-59.

Rhine, J. S. and Campbell, H. R. Thickness of facial tissues in American Blacks, Journal of Forensic Sciences (1980) 25:847-858.

Rhine, J. S. and Moore, C. E. Facial reproduction tables for facial tissue thickness of American Caucasoids in forensic anthropology. Maxwell Museum Technical Series No 1, 1982.

Stedman, T. L. Stedman's Medical Dictionary. Lippincott Williams and Wilkins, New York, 2000.

Suzuki, K. On the thickness of the soft parts of the Japanese face, Journal of the Anthropological Society of Nippon (1948) 60:7-11.

Taylor, K. T. Forensic Art and Illustration. CRC, New York, 2001.

White, T. D. Human Osteology. Academic, New York, 2000.

Table 1: Sparse Tissue-Depth Tables
Author Method of Collection Number of Landmarks

His (1895) needle with rubber stopper 15
Kollman and Büchly (1898) soot-covered needle 18
Suzuki (1948) needle 26
Rhine and Campbell (1980) needle with rubber stopper 32*
Rhine and Moore (1982) needle with rubber stopper 32*
Helmer (1984) ultrasound 34
George (1987) lateral radiograph 14
George (1993) not applicable 22†
Lebedinskaya et al. (1993) ultrasound 20
Aulsebrook et al. (1996) radiograph and ultrasound 54
Phillips and Smuts (1996) computed tomography 21‡
Manhein et al. (2000) ultrasound 19

* Rhine and Campbell (1980) and Rhine and Moore (1982) measured tissue depths at the same landmarks.

† George (1993) did not include tissue-depth measurements.

‡ Phillips and Smuts (1996) measured tissue depths at the same landmarks as Rhine and Campbell (1980), but they measured the lateral landmarks on only one side of the face.

Table 2: Landmarks on the Frontal Bone
  Symbol Landmark Definition in Text Reference

2.1 1 – v vertex undefined in referenced text* Helmer (1984)
  v vertex highest point of the skull George (1993)

2.2 b bregma intersection of the sagittal and coronal sutures George (1993)

2.3 st1 oberen stirnrand border of the forehead and the hair His (1895)
  st1 oberer stirnrand upper forehead edge, at the transition of the front forehead into the top of the head Kollmann & Büchly (1898)
  tr trichion undefined in referenced text* Suzuki (1948)
  2 – tr trichion undefined in referenced text* Helmer (1984)

2.4 m metopion undefined in referenced text* Suzuki (1948)
  1 supraglabella undefined in referenced text* Rhine & Campbell (1980)
  3 – m metopion undefined in referenced text* Helmer (1984)
  sg supraglabella undefined in referenced text* George (1987)
  1 metopion undefined in referenced text* Lebedinskaya et al. (1993)
  lr1 supraglabella between the maximum curvatures of the glabella and frontal eminence Aulsebrook et al. (1996)

2.5 4 – on ophryon undefined in referenced text* Helmer (1984)

2.6 st2 unteren stirnrand lower border of the forehead, at the glabella His (1895)
  st2 unterer stirnrand lower forehead edge, the highest elevation between the superciliary ridges Kollmann & Büchly (1898)
  g glabella undefined in refrence text* Suzuki (1948)
  2 glabella undefined in refrence text* Rhine & Campbell (1980)
  5 – g glabella undefined in refrence text* Helmer (1984)
  g glabella undefined in refrence text* George (1987)
  g glabella most prominent point between the supraorbital ridges in the midsagittal plane George (1993)
  3 glabella undefined in refrence text* Lebedinskaya et al. (1993)
  lr2 glabella maximum anterior convexities of glabella Aulsebrook et al. (1996)
  1 glabella approximately 1cm above and directly between the subject's eyebrows Manhein et al. (2000)

2.7 us2 lateral glabella soft tissue supraorbital ridge on a vertical line with the inner canthus of the eye Aulsebrook et al. (1996)

2.8 abr mitte der augenbrauen center of the eyebrow His (1985)
  abr mitte augenbrauen middle of the eyebrow, on the superciliary ridge, above the supraorbital foramen Kollmann & Büchly (1898)
  sc   — undefined in referenced text* Suzuki (1948)
  12 supraorbital undefined in referenced text* Rhine & Campbell (1980)
  18 – oa   — center over the border of the eyesocket Helmer (1984)
  2 superciliary undefined in referenced text* Lebedinskaya et al. (1993)
  or2 lateral supraorbital maximum curvature of the supraorbital ridge Aulsebrook et al. (1996)
  us3 supraorbital soft tissue supraorbital ridge in vertical alignment with the pupil of the eye Aulsebrook et al. (1996)
  9 superior eye orbit centered on eye, at level of eyebrow Manhein et al. (2000)

2.9 11 frontal eminence undefined in referenced text* Rhine & Campbell (1980)
  17 – stm   — center of the forehead, middle of over the eye socket on the connecting line from the frontotemporale to the metopion Helmer (1984)
  us1 frontal on the forehead in a vertical line with the pupil of the eye and on the same horizontal level as radiographic points supraglabella and lateral frontal Aulsebrook et al. (1996)

2.10 or1 lateral frontal deepest point in the depression between the frontal eminence and the maximum curve of the supraorbital margin Aulsebrook et al. (1996)

2.11 ft frontotemporale undefined in referenced text* Suzuki (1948)
  24 – ft frontotemporale undefined in referenced text* Helmer (1984)

* See Table 10

Table 3: Landmarks on the Temporal Bone
  Symbol Landmark Definition in Text Reference

3.1 te   — undefined in referenced text* Suzuki (1948)
  30 – mt   — on the muscle temporalis above the zygion at the height of the ektokonchion Helmer (1984)

3.2 jb wurzel des jochbogens in front of the ear, above the zygomatic arch His (1895)
  jb wurzel des jochbogens vor dem ohr root of the zygomatic arch before the ear, vertically over the bony external ear at the sharp edge of the zygomatic process Kollmann & Büchly (1898)
  17 supraglenoid undefined in referenced text* Rhine & Campbell (1980)
  us7 root of the zygoma immediately above the mandibular condyle and superficial to the posterior root of the zygoma Aulsebrook et al. (1996)
  19 root of zygoma anterior to and 0.5cm superior to tragus Manhein et al. (2000)

3.3 jb1 grösste distanz der jochbogen largest distance of the zygomatic arch Kollmann & Büchly (1898)
  zy zygion undefined in referenced text* Suzuki (1948)
  16 zygomatic arch, midway undefined in referenced text* Rhine & Campbell (1980)
  31 – zy zygion undefined in referenced text* Helmer (1984)
  zy zygion most lateral point on the zygomatic arch George (1993)
  9 zygion undefined in referenced text* Lebedinskaya et al. (1993)
  or4 lateral zygomatic maximum, most lateral curvature of the zygomatic bone Aulsebrook et al. (1996)
  us6 midzygomatic on the maximum horizontal and vertical outer curvature of the zygomatic arch Aulsebrook et al. (1996)

* See Table 10

Table 4: Landmarks on the Zygomatic Bone
  Symbol Landmark Definition in Text Reference

4.1 wb höchster punkt des wangenbeinhöckers highest point of the cheekbone bump, place of the highest elevation of the cheek over the cheek bone Kollmann & Büchly (1898)
  ma ektokonchion & zygomaxillare, midway undefined in referenced text* Suzuki (1948)
  15 lateral orbit undefined in referenced text* Rhine & Campbell (1980)
  26 – wh  —  cheekbone approximately at the height of the frankfort horizontal Helmer (1984)
  8 malare undefined in referenced text* Lebedinskaya et al. (1993)
  or6 inferior border of zygomatic lowest point on the inferior curvature of the zygomatic bone as seen on the oblique profile Aulsebrook et al. (1996)
  17 zygomatic lined up with the lateral border of the eye on the zygomatic process Manhein et al. (2000)

4.2 ek ektokonchion undefined in referenced text* Suzuki (1948)
  25 – ek ektokonchion undefined in referenced text* Helmer (1984)
  ec ektokonchion most lateral point of the lateral wall of the orbit George (1993)
  or3 lateral orbit deepest curvature of the lateral orbital margin Aulsebrook et al. (1996)
  16 lateral eye orbit lined up laterally with the corner of the eye Manhein et al. (2000)

4.3 ua mette des unteren augenhöhlenrandes center of the lower border of the eye socket His (1895)
  ua mitte unterer augenhöhlenrand middle of the lower eye sockets edge, also the union of the cheek bone and the zygomatic process of the upper jaw Kollmann & Büchly (1898)
  or orbitale undefined in referenced text* Suzuki (1948)
  13 suborbitale undefined in referenced text* Rhine & Campbell (1980)
  19 – or orbitale undefined in referenced text* Helmer (1984)
  or orbitale most inferior point on the margin of the orbit George (1993)
  us5 infraorbital on the flat plane lying just below the lower rim of the eye socket and in vertical alignment with the pupil of the eye Aulsebrook et al. (1996)
  10 inferior eye orbit centered on eye, where inferior bony margin lies Manhein et al. (2000)

* See Table 10

Table 5: Landmarks on the Nasal Bone
  Symbol Landmark Definition in Text Reference

5.1 nw an der nasenwurzel at the root of the nose, in the angle His (1895)
  nw an der nasenwurzel at the root of the nose, the deepest place of the transition of the nasal process and the forehead Kollmann & Büchly (1898)
  n nasion undefined in referenced text* Suzuki (1948)
  3 nasion undefined in referenced text* Rhine & Campbell (1980)
  6 – n nasion undefined in referenced text* Helmer (1984)
  n nasion undefined in referenced text* George (1987)
  n nasion midpoint of the suture between the frontal and the two nasal bones George (1993)
  4 nasion undefined in referenced text* Lebedinskaya et al. (1993)
  ir3 nasion midpoint of the fronto-nasal suture Aulsebrook et al. (1996)
  2 nasion directly between eyes Manhein et al. (2000)

5.2 nr am knöchernen nasenrücken at the bony ridge of the nose His (1895)
  nr nasenbeinmitte middle of the bony nose Kollmann & Büchly (1898)
  n'  —  undefined in referenced text* Suzuki (1948) (1898)
  7 – nm nasenbeinmitte middle of the bony nose Helmer (1984)
  nr4 midnasal lying midway between nasion and rhinion Aulsebrook et al. (1996)

5.3 ns nasenbeinspitze tip of the bony nose Kollmann & Büchly (1898)
  rhi rhinion undefined in referenced text* Suzuki (1948)
  4 end of nasal undefined in referenced text* Rhine & Campbell (1980)
  8 – rhi rhinion undefined in referenced text* Helmer (1984)
  na nasale undefined in referenced text* George (1987)
  na nasale anterior tip of the nasal bones at their junction with the lateral nasal cartilages George (1993)
  5 rhinion undefined in referenced text* Lebedinskaya et al. (1993)
  lr5 rhinion lowest point on the internasal suture Aulsebrook et al. (1996)
  3 end of nasals palpating to determine where bone ends and cartilage begins Manhein et al. (2000)

* See Table 10

Table 6: Landmarks on the Maxilla
  Symbol Landmark Definition in Text Reference

6.1 da dacryon junction of the frontal, maxillary, and lacrimal bones on the medial wall of the orbit George (1993)

6.2 ni  —  undefined in referenced text* Suzuki (1948)
  9 – na  —  lateral offset of the nasal bone in the frankfurt horizontal plane Helmer (1984)
  6 lateral point of the nose undefined in referenced text* Lebedinskaya et al. (1993)
  us4 lateral nasal side of the bridge of the nose at the same horizontal level as midnasal and on a vertical line with the inner canthus of the eye Aulsebrook et al. (1996)

6.3 al alare undefined in referenced text* Suzuki (1948)
  10 – al alare undefined in referenced text* Helmer (1984)
  al alare most lateral point on the nasal aperture George (1993)
  or5 lateral alare measurement of distance the nose tip projects beyond the oblique profile Aulsebrook et al. (1996)
  4 lateral nostril approximately 0.5cm to the right of the nostril Manhein et al. (2000)

6.4 20 – fc fossa canina undefined in referenced text* Helmer (1984)
  10 supracanina undefined in referenced text* Lebedinskaya et al. (1993)
  or7 subzygomatic deepest indentation between the zygomatic bone and maxilla as seen on the oblique profile Aulsebrook et al. (1996)

6.5 14 inferior malar undefined in referenced text* Rhine & Campbell (1980)
  27 – zm zygomaxillare undefined in referenced text* Helmer (1984)
  7 maxillary undefined in referenced text* Lebedinskaya et al. (1993)
  or8 subalare on the outer curvature of the maxilla halfway between subzygomatic and lateral upper-lip margin Aulsebrook et al. (1996)

6.6 m1  —  undefined in referenced text* Suzuki (1948)
  21 supra-m2 undefined in referenced text* Rhine & Campbell (1980)
  21 – ms oberer erster molar above the first molar Helmer (1984)
  or9 lateral upper-lip margin maximum labial curvature of the crown of the upper canine Aulsebrook et al. (1996)
  us9 supralabial over the maximum bulge of the canine eminence midway between the angle of the mouth and the root of the alare cartilage Aulsebrook et al. (1996)
  13 supra m2 cheek region, lateral: lined up with bottom of nose; vertical: lined up beneath lateral border of eye Manhein et al. (2000)

6.7 us10 supracommissural on a horizontal level with supralabial and on a vertical line with commissural Aulsebrook et al. (1996)

6.8 ol1 an der wurzel der oberlippe at the root of the upperlip, just under the nasal septum His (1895)
  ow oberlippenwurzel root of the upperlip, in the angle where the upperlip meets the partition of the nose Kollmann & Büchly (1898)
  sn subnasale undefined in referenced text* Suzuki (1948)
  11 – sn subnasale undefined in referenced text* Helmer (1984)
  lr6 anterior nose tip acanthion to most anterior cure of the nose tip Aulsebrook et al. (1996)
  lr7 inferior nose tip acanthion to lowest curve of the nose tip Aulsebrook et al. (1996)
  lr8 midcolumella base acanthion to subnasale Aulsebrook et al. (1996)

6.9 ol2 im lippengrübchen in the dimple of the upper lip His (1895)
  lg lippengrübchen lips dimple, that place of the deepest decline of the lips furrow (philtrum) Kollmann & Büchly (1898)
  5 midphiltrum lips dimple, that place of the deepest decline of the lips furrow (philtrum) Rhine & Campbell (1980)
  a Point A - superior labial sulcus (SLS) undefined in referenced text* George (1987)
  ns nasospinale intersection of line between lower margins of nasal apertures and midsagittal plane George (1993)
  a Point A / subspinale deepest midline point on the indentation between the anterior nasal spine and the supradentale George (1993)
  11 philtrum undefined in referenced text* Lebedinskaya et al. (1993)
  lr9 midphiltrum point A / subspinale Aulsebrook et al. (1996)
  us8 philtrum ridge lateral ridge of the philtrum midway between the angle of the mouth and the root of the alar cartilage Aulsebrook et al. (1996)
  5 midphiltrum centered between nose and mouth Manhein et al. (2000)

6.10 6 upper lip margin undefined in referenced text* Rhine & Campbell (1980)
  12 – ls labrale superius undefined in referenced text* Helmer (1984)
  ls labrale superius undefined in referenced text* George (1987)
  sd supradentale / alveolare / prosthion apex of the alveolus in the midline between the maxillary central incisors George (1993)
  12 upper lip undefined in referenced text* Lebedinskaya et al. (1993)
  lr10 midupper-lip margin maximum labial curvature of the most anteriorly placed upper central incisor Aulsebrook et al. (1996)
  11 supra canine upper lip, lined up superiorly/inferiorly with lateral edge of nostril Manhein et al. (2000)

6.11 sto stomion undefined in referenced text* George (1987)
  ls inscisor superius tip of the crown of the most anterior maxillary central incisor George (1993)
  lr11 midlipline maximum lower curvature of the incisal edge of the most anterior of the two upper central incisors Aulsebrook et al. (1996)
  or10 angle of the mouth maximum curvature of the rounded incisal tip of the canine Aulsebrook et al. (1996)
  or11 lateral lipline maximum curvature of the rounded incisal tip of the canine to the junction of the upper and lower lips Aulsebrook et al. (1996)

* See Table 10

Table 7: Landmarks on the Mandible
  Symbol Landmark Definition in Text Reference

7.1 7 lower lip margin undefined in referenced text* Rhine & Campbell (1980)
  13-li labrale inferius undefined in referenced text* Helmer (1984)
  ll labrale inferius undefined in referenced text* George (1987)
  ld infradentale apex of the alveolus in the midline between the mandibular central incisors George (1993)
  13 lower lip undefined in referenced text* Lebedinskaya et al. (1993)
  lr12 midlower-lip margin point on the maximum labial curvature of the most anteriorly placed lower central incisor Aulsebrook et al. (1996)
  or12 lateral lower-lip margin maximum labial curvature of the crown of the mandibular canine Aulsebrook et al. (1996)
  12 subcanine lower lip, lined up superiorly/inferiorly with lateral edge of nose Manhein et al. (2000)

7.2 m1  —  undefined in referenced text* Suzuki (1948)
  20 sub-m2 undefined in referenced text* Rhine & Campbell (1980)
  22 – mi uterer erster molar below the first molar Helmer (1984)
  us13 sublabial within the labiomental crease in vertical alignment with supralabial Aulsebrook et al. (1996)
  14 lower cheek cheek region, lateral: lined up with mouth, vertical: same as supra m2 Manhein et al. (2000)

7.3 18 occlusal line undefined in referenced text* Rhine & Campbell (1980)
  us11 commissural on a horizontal level with the cheilion and immediately posterior to the commissural bulge Aulsebrook et al. (1996)

7.4 us14 subcommissural in a vertical line with supracommissural lying on a horizontal level with sublabial Aulsebrook et al. (1996)

7.5 k1 in der kinnlippenfurche In the chin-lip groove His (1895)
  lf kinnlippenfurche chin lips furrow, on the decline between lower teeth and the mental protuberance Kollmann & Büchly (1898)
  ml  —  undefined in referenced text* Suzuki (1948)
  8 chin-lip fold undefined in referenced text* Rhine & Campbell (1980)
  14 – slm sulcus-labio-mentalis undefined in referenced text* Helmer (1984)
  b point B - inferior labial sulcus (ils) undefined in referenced text* George (1987)
  b point B / supramentale the deepest midline point on the indentation between the infradentale and pogonion George (1993)
  14 chin fissure undefined in referenced text* Lebedinskaya et al. (1993)
  lr13 midlabio-mental point B / supramentale Aulsebrook et al. (1996)
  or13 lateral labio-mental deepest curvature of the mandible as seen on the oblique radiograph Aulsebrook et al. (1996)
  oo14 lateral point B deepest curvature of the mandible as seen on the oblique radiograph Aulsebrook et al. (1996)
  6 chin-lip fold centered in fold of chin, below lips Manhein et al. (2000)

7.6 spog suprapogonion undefined in referenced text* George (1987)

7.7 k2 am kinnwulst in the highest point of the chin bulge His (1895)
  kw kinnwulst chin bulge, the highest front elevation of the mental protuberance of the lower jaw Kollmann & Büchly (1898)
  pg pogonion undefined in referenced text* Suzuki (1948)
  9 mental eminence undefined in referenced text* Rhine & Campbell (1980)
  15 – pg pogonion undefined in referenced text* Helmer (1984)
  pog pogonion undefined in referenced text* George (1987)
  pog pogonion most anterior point in the midline on the mental protuberance George (1993)
  15 chin undefined in referenced text* Lebedinskaya et al. (1993)
  lr14 anterior symphyseal maximum forward curvature of the mental prominence (pogonion) Aulsebrook et al. (1996)
  or15 lateral mental maximum lateral convexity of the mental protuberance as seen on the oblique radiograph Aulsebrook et al. (1996)
  or16 lateral mental maximum lateral convexity of the mental protuberance as seen on the oblique radiograph Aulsebrook et al. (1996)
  7 mental eminence centered on forward-most projecting point of chin Manhein et al. (2000)

7.8 k3 unter dem kinn under the chin, at the lowest height on the mandible His (1895)
  k3 unter dem kinn under the chin, the vertical measure of the soft tissue on the lower edge of the mental protuberance Kollmann & Büchly (1898)
  gn gnathion undefined in reference text* Suzuki (1948)
  10 beneath chin undefined in reference text* Rhine & Campbell (1980)
  16 – gn gnathion undefined in reference text* Helmer (1984)
  gn gnathion undefined in reference text* George (1987)
  me menton undefined in reference text* George (1987)
  gn gnathion a constructed point midway between the most anterior (pogonion) and most inferior (menton) points on the chin George (1993)
  me menton lowest point on the mandible George (1993)
  16 gnathion undefined in referenced text* Lebedinskaya et al. (1993)
  lr15 intermediate symphyseal outer surface of the bone midway between anterior and inferior symphyseal points Aulsebrook et al. (1996)
  lr16 inferior symphyseal lowest point on the curve of the body chin (menton) Aulsebrook et al. (1996)
  or17 intermediater mental maximum convexity of the body of the mandible halfway between points lateral mental and inferior mental Aulsebrook et al. (1996)
  or18 intermediate mandibular maximum convexity of the body of the mandible halfway between points lateral mental and inferior mental Aulsebrook et al. (1996)
  or20 inferior mandibular on lower body of the mandible, on a vertical line running at right angles to a line that passes horizontally through lateral mental Aulsebrook et al. (1996)
  8 beneath chin centered on inferior surface on mandible Manhein et al. (2000)

7.9 us15 mental tubercle, anterior most prominent point on the lateral bulge of the chin mound Aulsebrook et al. (1996)

7.10 23 – ur  —  border of the mandible, below the upper cuspid Helmer (1984)

7.11 17 middle of the mandibular body undefined in referenced text* Lebedinskaya et al. (1993)
  us16 mental tubercle, lateral posterior to and horizontal to mental tubercle, anterior, on the same vertical alignment with supracommissural and subcommissural Aulsebrook et al. (1996)

7.12 uk vor dem m. masseter along the edge of the mandible, in front of the masseter muscle His (1895)
  uk vor dem masseter am unterkiefer front border of the masseter muscle on the lower jaw Kollmann & Büchly (1898)
  28 – ml  —  mandible in front of the masseter muscle Helmer (1984)
  18 lower margin of the mandible undefined in referenced text* Lebedinskaya et al. (1993)
  us17 insertion of masseter, anterior anterior edge of the insertion of the masseter muscle into the mandible Aulsebrook et al. (1996)
  15 midmandible inferior border of mandible, vertical lined up with same as supra m2 Manhein et al. (2000)

7.13 us18 insertion of masseter, posterior lower and posterior edge of the insertion of masseter into the mandible, just anterior to the gonion Aulsebrook et al. (1996)

7.14 kw am kieferwinkel at the angle of the mandible His (1895)
  kw am kieferwinkel at the jaw angle Kollmann & Büchly (1898)
  go gonian undefined in referenced text* Suzuki (1948)
  19 gonian undefined in referenced text* Rhine & Campbell (1980)
  33 – go gonian undefined in referenced text* Helmer (1984)
  go gonian a constructed point, intersection of the lines tangent to the posteror margin of the ascending ramus and the mandibular base, or the most lateral point at the mandibular angle George (1993)
  20 gonian undefined in referenced text* Lebedinskaya et al. (1993)
  18 found by palpating undefined in referenced text* Manhein et al. (2000)

7.15 ms mitte d. m. masseter at the half-way elevation along the masseter muscle, on the mandible His (1895)
  ms mitte des masseter middle of the masseter muscle, the halfway point of the stretch between the lower edge of the cheekbone and the angle of the lower jaw Kollmann & Büchly (1898)
  ms zygion & gonion, midway undefined in referenced text* Suzuki (1948)
  32 – m2  —  center of the masseter between the gonion and zygion Helmer (1984)
  19 mandibular branch undefined in referenced text* Lebedinskaya et al. (1993)
  us12 midmasseteric lying over the center of an area bounded by the lower borders of the zygomatic arch and mandible Aulsebrook et al. (1996)

* See Table 10

Table 8: Landmarks on the Occipital Bone
  Symbol Landmark Definition in Text Reference

8.1 op opisthokranion undefined in referenced text* Suzuki (1948)
  34 – op opisthokranion undefined in referenced text* Helmer (1984)

8.2 I inion at the base of the external occipital protuberance George (1993)

* See Table 10

Table 9: Landmarks on the Parietal Bone
  Symbol Landmark Definition in Text Reference

9.1 l lambda intersection of the sagittal and lambdoidal sutures George (1993)

9.2 eu eurion undefined in referenced text* Suzuki (1948)
  29 – eu euryon undefined in referenced text* Helmer (1984)

* See Table 10

Table 10: Common Definitions of Landmarks
Landmark Definition Reference Table
alare the instrumentally determined most lateral point on the nasal aperture taken perpendicular to the nasal height Bass (1995) 6
beneath chin the lowest point on the mandible Taylor (2001) 7
chin the anterior projection of the inferior border of the body of the mandible Bass (1995) 7
chin fissure a deep furrow, cleft, or slit in the chin Stedman (2000) 7
chin-lip fold a ridge or margin apparently formed by the doubling back of a lamina between the chin and lip Stedman (2000) 7
ectoconchion the point where the orbital length line, parallel to the upper border, meets the outer rim. The point of maximum breadth on the lateral wall of the eye orbit Bass (1995) 4
end of nasal the anterior tip or the farthest point {it out} on the nasal bones Taylor (2001) 5
euryon the two points on the opposite sides of the skull that form the termini of the lines of greatest breadth Bass (1995) 9
fossa canina hollow of variable extent located on the facial surface just below the infraorbital formamen, where the zygomatic, frontal, and alveolar processes of the maxilla come together White (2000) 6
frontal eminence bony projection of the ectocranial surface of the frontal bone White (2000) 2
frontotemporale the most medial point on the incurve of the temporal ridge, the points lie on the frontal bones just above the zygomaticofrontal suture. Bass (1995) 2
glabella the most forward projecting point in the midline of the forehead at the level of the supraorbital ridges and above the nasofrontal suture Bass (1995) 2
gnathion the lowest median point on the lower border of the mandible Bass (1995) 7
gonion the midpoint of the angle of the mandible between body and ramus Bass (1995) 7
inferior labial sulcus a furrow between the developing lower lip and gum Stedman (2000) 7
inferior malar the lowest part of the cheek, or cheek bone Stedman (2000) 6
labrale inferius a point where the boundary of the vermilion border of the lower lip and the skin is intersected by the median plane Stedman (2000) 7
labrale superius the point on the upper lip lying in the median sagittal plane on a line drawn across the boundary of the vermilion border and skin Stedman (2000) 6
lateral orbit drop a line from the outer margin of the orbit and place the marker about 10mm below the orbit Taylor (2001) 4
lower lip margin centered between the mandibular (lower) central incisors at the level of the cementum enamel junction Taylor (2001) 7
m1 the first upper molar Bass (1995) 6
m1 the first lower molar Bass (1995) 7
mandibular body the thick bony part of the mandible that anchors the teeth White (2000) 7
mandibular branch the mandibular ramus; the upturned perpendicular extremity of the mandible on either side Stedman (2000) 7
maxillary relating to the maxilla, or upper jaw Stedman (2000) 6
mental eminence the triangular eminence, or bony chin, at the base of the corpus in the anterior symphyseal region (mental protuberance) White (2000) 7
menton in cephalometrics, the lowermost point in the symphyseal shadow as seen on a lateral jaw projection Stedman (2000) 7
metopion an instrumentally determined, ectocranial midline point on the frontal where the frontal's elevation above the chord from the nasion to the bregma is the greatest White (2000) 2
nasion intersection of the nasofrontal suture with the midsagittal plane Bass (1995) 5
occlusal line line pertaining to the contacting surfaces of the posterior teeth Stedman (2000) 7
ohryon the point on the midline of the forehead just above the glabella (supranasal point, supraorbital point) Stedman (2000) 2
opisthocranion the most posterior point on the skull not on the external occipital protuberance; the posterior end point of maximum cranial length measured from glabella Bass (1995) 8
orbitale the lowest point in the margin of the orbit Bass (1995) 4
piltrum the infranasal depression; the groove in the midline of the upper lip Stedman (2000) 6
pogonion the most anterior point in the midline of the chin Bass (1995) 7
rhinion the midline point at the inferior free end of the internal suture White (2000) 5
stomiom the median point of the oral slit when the lips are closed Stedman (2000) 6
sub-m2 below the second lower molar Bass (1995) 7
subnasale under the nose Stedman (2000) 6
suborbital infraorbital, below or beneath the orbit Stedman (2000) 4
sulcus-labio-mentalis the indistinct line separating the lower lip from the chin Stedman (2000) 7
superciliary arches curved projections above orbits (brow ridges) Bass (1995) 2
superior labial sulcus a furrow between the developing upper lip and gum Stedman (2000) 6
supracanine above the canine tooth Bass (1995) 6
supraglabella a position above the glabella Stedman (2000) 2
supraglenoid above the glenoid cavity or fossa Stedman (2000) 3
supra-m2 above the second upper molar Bass (1995) 6
supraorbital border upper edge of the eye orbit Bass (1995) 2
suprapogonion a position above the pogonion Stedman (2000) 7
trichion a cephalometric point at the midpoint of the hairline at the top of the forehead Stedman (2000) 2
upper lip margin centered between the maxillary (upper) central incisors at the level of the cementum enamel junction Taylor (2001) 6
vertex the highest point in the midsagittal contour, as seen from norma lateralis, when the cranium is in the frankfort horizontal Bass (1995) 2
zygion the most lateral point of the zygomatic arch; a point determined instrumentally Bass (1995) 3,7
zygomatic arch the arch formed by the temporal process of the zygomatic bone that joins the zygomatic process of the temporal bone Stedman (2000) 3
zygomaxillare the most inferior point on the zygomaticomaxillary suture White (2000) 4,6

Figures

Representation of landmarks on the frontal bone: vertex, bregma, trichion, metopion, ophryon, glabella, lateral glabella, supraorbital, frontal eminence, lateral frontal, frontotemporale.

Figure 1: Representation of landmarks on the frontal bone: 2.1, vertex; 2.2, bregma; 2.3, trichion; 2.4, metopion; 2.5, ophryon; 2.6, glabella; 2.7, lateral glabella; 2.8, supraorbital; 2.9, frontal eminence; 2.10, lateral frontal; 2.11, frontotemporale.

Representation of landmarks on the temporal bone:temporal fossa, root of zygoma, zygion.

Figure 2: Representation of landmarks on the temporal bone: 3.1, temporal fossa; 3.2, root of zygoma; 3.3, zygion.

Representation of landmarks on the zygomatic bone:zygomatic, ectoconchion, orbitale.

Figure 3: Representation of landmarks on the zygomatic bone: 4.1, zygomatic; 4.2, ectoconchion; 4.3, orbitale.

Representation of landmarks on the nasal bone: nasion, midnasal, rhinion.

Figure 4: Representation of landmarks on the nasal bone: 5.1, nasion; 5.2, midnasal; 5.3, rhinion.

Representation of landmarks on the maxilla: dacryon, lateral nasal, alare, fossa canina, zygomaxillare, supra-M2, supracommissural, subnasale, midphiltrum;, prosthion, stomion.

Figure 5: Representation of landmarks on the maxilla: 6.1, dacryon; 6.2, lateral nasal; 6.3, alare; 6.4, fossa canina; 6.5, zygomaxillare; 6.6, supra-M2; 6.7, supracommissural; 6.8, subnasale; 6.9, midphiltrum; 6.10, prosthion; 6.11, stomion.

Representation of landmarks on the mandible: infradentale, sub-M2, occlusal line, subcommissural, chin-lip fold, suprapogonion, pogonion, gnathion, mental tubercle, anterior, border of the mandible, middle of the mandibular body, insertion of masseter, anterior, insertion of masseter, posterior, gonion, mandibular branch.

Figure 6: Representation of landmarks on the mandible: 7.1, infradentale; 7.2, sub-M2; 7.3, occlusal line; 7.4, subcommissural; 7.5, chin-lip fold; 7.6, suprapogonion; 7.7, pogonion; 7.8, gnathion; 7.9, mental tubercle, anterior; 7.10, border of the mandible; 7.11, middle of the mandibular body; 7.12, insertion of masseter, anterior; 7.13, insertion of masseter, posterior; 7.14, gonion; 7.15, mandibular branch.

Representation of landmarks on the occipital and parietal bones: opisthocranion, inion, lambda, euryon.

Figure 7: Representation of landmarks on the occipital and parietal bones: 8.1, opisthocranion; 8.2, inion; 9.1, lambda; 9.2, euryon.