Craniometric point

Abbreviation

Definition

Asterion

ast

Where the lambdoid, parietomastoid, and occipitomastoid sutures meet.

Basion

ba

Basion encompasses a small region, in the median plane at the most anterior extension of the foramen magnum. Its position as a reference point varies slightly depending on the measurement being taken. It may be the most posterior aspect of the anterior border of the foramen magnum or the most inferior midpoint of the anterior border of the foramen magnum (as used to measure skull height).

Bregma

b

Where the sagittal and coronal sutures meet. Impossible to determine in juvenile skulls with anterior fontanelle, or with complete obliterated suture.

Inion

i

Midpoint between the vertices of the upper nuchal lines and at the base of the external occipital protuberance (not the tip of the protuberance).

Lambda

l

Point where the two branches of the lambdoid suture and the sagittal suture meet (project from the main direction of the sutures in cases of obliteration or presence of vermiform bones).

Nasion

n

Intersection of the nasofrontal sutures in the median plane.

Opisthion

o

Midpoint on the anterior side of the posterior border of the foramen magnum.

Pterion

pt

A circular region, marked by the sphenoparietal suture at its center. This region marks the thinnest part of the cranial vault.

Stephanion

st

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

Glabella

g

Most anterior point of the midline on the forehead, in the region of the superciliary ridges

Opisthocranion

op

Most prominent posterior point overlying the occipital bone, which produces the greatest head length from glabella