Glossary of Osteometric Landmarks and Anatomical Regions

Acanthion

The point at the base of the anterior nasal spine.

Alveolare

The inferiormost point of the alveolar margin between the maxillary central incisors; often confused with prosthion. Compare with infradentale and prosthion.

Alveolon

The point on the hard palate at which a !in~· drawn through the distal margin of the maxillary alveolar processes intersects the median sagittal plane.

Apex

The highest point on the skull, which also lies in the same vertical plane as porion; the skull must be in the Frankfort horizontal.

Basion

A point at the midline of the anterior border of the foramen magnum. 2. A point at the position pointed to by the apex of the triangular surface at the base of either condyle (i.e., the average position from the crests bordering this area), about halfway between the inner border directly facing the posterior border (the opisthion) and the lowermost point on the border (i.e., between endobasion and hypobasion); it is the same as endobasion if the anterior border of the foramen magnum is thin and sharp (Howells, 1973).

Bregma

The juncture of the coronal and sagittal sutwes in the median sagittal plane; should an ossicle be present, the landmark can be located by drawing in pencil a continuation of the sutures until these lines intersect.

Endobasion

The most posterior point on the mid.line of the anterior margin of the foramen magnum; it is usually behind and below basion but coincident with it when the margin is thin and sharp.

Glabella

The anteriormost region (not a point) of the frontal bone above the frontonasal suture and between the superdliary arches. This region generally protrudes anteriorly, but in certain skulls this region may be flat ("hyperfeminine" skulls, infants, and juveniles) or even depressed. When it is not protrusive, glabella may be identified by a change in the direction of the frontal bone.

Gnathion

The "lowest" (anterior- and inferiormost) point on the chin.

Incision

The point of contact [identified on the buccal Qabial) sideJ between the mesial ocdusal edges of the upper central incisors.

lnfradentale

The superiormost point of the alveolar margin (identified on the anterior surface) between the mandibular central incisors.

Inion

A point at the midline of the superior nuchal lines, which often coincides but should not be identified with the base of the external occipital protuberance. Measurement should not be taken from the protuberance.

Lambda

The juncture in the median sagittal plane of the lambdoid and sagittal sutures; should an osside be present, the landmark is located by drawing in pencil a continuation of the sutures until these lines intersect.

Nasion

The juncture in the median (sagittal) plane of the frontonasal and (inter)nasal sutures.

Nasospinale

A midline point on a line drawn through the inferiormost margins of the nasal aperture; it may coincide but is not synonymous with acanthion.

Obelion

The point of intersection between a line drawn through the two parietal foramina and the sagittal suture.

Ophryon

A midline point on a line drawn across the forehead and which lies on a plane that passes through right and left frontotemporale.

Opisthion

A point in the midllne of the posterior margin of the foramen magnum.

Opisthocranion

The most posterior point on midline of the skull when th; skull is oriented in the Frankfort horirontal.

Orale

The point of intersection of a line drawn through the lingualmost surfaces of the upper central incisors and the midline of the premaxillary region.

Pogonion

The anteriormost midline point of the chin; it lies anterior to and above gnathion.

Prosthion

The anteriormost mid.line point on the premaxillary alveolar process in the median (sagittal) plane; it is located slightly above alveolare, with which it is often confused.

Rhinion

The lnferiormost point on the (inter)nasal suture.

Staphylion

The midline point of a line drawn through the anteriormost invaginations of the posterior margins of the right and left palatine bones; it t:y'pically falls anterior to the posterior nasal spine.

Subspinale

The deepest midline point in the concavity between the anterior nasal spine and the premaxillary alveolar; it is located on the crest of the midline suture.

Vertex

The highest midline point on the skull when the skull is in the Frankfort horizontal; it may coincide with apex.

Bilateral

(paired) landmarks of the skull

Alare

The lateralmost point on the margin of the nasal aperture.

Asterion

The juncture of the temporal, parietal, and occipital bones (also of the lambdoid, temporoparietal, and occipitOmastoid sutures).

Condylion laterale

The most lateral point on the mandibular condyle.

Coronale

The most lateral point on the coronal suture.

Dacryon

1. (Traditional; considered obsolete by· Vallois, 1965) The juncture of the frontolacrimal,'frontomaxillary, and lacrimomaxillary sutures; lies between lacrimale and maxillofrontale. 2. "The apex of the lacrimal fossa, as it impinges on the frontal bone" (Howells, 1973, p. 167); considered to be more easily located and useful in anteroposterior measurements.

Ectoconchion

The anteriormost point on the lateral rim of the orbit that contributes to the determination of maximum orbital breadth (as measured from dacryon or maxillofrontale); this point is also used in the measurement of facial flatness.

Ectomolare

The most lateral extent of the alveolar process in the middle of the second maxillary molar on its buccal side

Endomolare

The most medial extent of the alveolar process in the middle of the second maxillary molar on its lingual side.

Euryon

The point that, on a parietal, contributes to the determination of maximum (biparietal) cranial breadth.

Frontomalare anterior

The most anteriorly prominent point on the zygomaticofrontal suture.

Frontotemporale

The point at which the temporal ridge is most inwardly or medially curved; also, the point which contributes to the determination of minimum frontaJ breadth.

Gonion

The intersection of a line tangent to the posterior margin of the ascending ramus and a line tangent to the inferior margin of the body of the mandible; also, the most marked point of transition in the -upward curvature of the posteroinferior margin of the mandible.

Jugale

The juncture on the posterior margin of the zygomatic: bone of the horizontal and vertical portions (i.e., temporal and frontal processes, respectively) of this bone.

Krotaphion

The juncture of the sphenoparietal, sphenotemporal, and squamosal sutures; the location of this landmark must be estimated on those individuaJs in whom there is frontotemporal articulation.

Lacrimale

The juncture of the posterior lacrimal crest and the frontolacrimal suture; lies posterior to dacryon.

Mastoidale

The inferiormost point on the mastoid process when the skull is in the Frankfort horizontal.

Maxillofrontale

The juncture of the anterior lacrimal crest and the frontomaxillary suture; lies anterior to dacryon.

Mentale

The anteriormost point on the margin of the mental foramen (mandible).

Nariale

The most inferior extent of the anterior margin of the nasal aperture on om; side or the other of the anterior nasal spine.

Orbitale

The most inferior point on the orbital rim; used with porion to orient the skull in the Frankfort horizontal.

Porion

The most lateral point on the superior margin of the external auditory (acoustic) meatus; it is located vertically over the center and thus at the middle of the superior margin of the meatus.

Pterion

A region (not a point) delineated by the frontal bone anteriorly, the squamous portion of the temporal bone posteriorly, and the area along the sphenoparietal suture; the landmark would not be recognized in those individuals with frontotemporal articulation

Sphenion

The juncture of the frontal bone with the parietal bone, the greater wing of the sphenoid, and the squamous portion of the temporal bone.

Stephanion

The point at which the inferior temporal line crosses the coronal suture.

Zygion

The most lateral point 'on the zygomatic arch.

Zygomaxillare anterior

The point on the facial (anterior) surface where the zygomaticomaxillary suture intersects the attachment scar of the masseter muscle; considered more appropriate than zygomaxillare (inferior) for measuring flatness/protrusion of the face.

Zygomaxillare (inferior)

The most inferior point on the zygomaticomaxillary suture

Zygoorbitale

The juncture of the zygomaticomaxillary suture with the inferior orbital rim