Jaw shapes, types and classifications

In this article, I will examine the different kinds of lower jaw shapes when viewed from the profile.
I will establish a classification system that will help categorize the lower jaws based on 3 criterions:

  • The gonial angle of the jaw
  • The projection of the chin
  • The shape of the jawline

After reading this article, you will be able to classify any jawline when viewed from the profile.
This site is unique in the sense that it advances the science of square jaw appreciation ^^.

Note that this is applicable to both women and men. Jaw squareness is NOT a sexual characteristic. Neither a guarantee of beauty.


This is the angle of the jaw, circled in green.

C grade
A jaw with a C grade for the angle has no visible gonial angle apparent, or the angle is round. The jaw seems to go straight from the bottom of the ear lobe to the point of the chin.
It doesn’t mean that the jaw bone has no angle of course… there is always some sort of angle on the bone… but the ramus has very little height and the angle is very obtuse, giving the appearance of a jaw with no or rounded angle.

Jaw shape classification: weak angle

B grade
With the B grade, there is a noticeable jaw angle. Angle is obtuse, not square, but robust and prominent.
Jaw shape classification: medium square angle

A grade
The A grade jaw angle is a perfect or almost perfect square. These kind of jaw angles are VERY rare.
The face is fully developed. More developed than other types of faces that are in some way atrophic versions of this ideal type.
Ramus height is very tall.

Jaw shape classification: Square angle


I draw a (green) line perpendicular to a horizontal floor line. This line must touch the lower lip.

C grade
The chin recedes behind the chin projection line.

Jaw shape classification: receding chin

B grade
The chin extends to the projection line. It is a sign of a well-developed face; the jaw has benefited from more growth length than the C grade.

Jaw shape classification: normal chin

A grade
On the grade A, the chin extends beyond the chin extension line. In the case illustrated in the image below, you can see that the chin extends even further than the upper lip !
Two remarks:
It is not only a “lengthy chin” that creates this kind of physique. It’s the whole jaw that is horizontally well developed that pushes the chin forward.
Grade A can happen in abnormal, diseased physique with a disproportional growth of the face. It is rare to find a healthy face with a chin grade A, but a genuine healthy chin grade A as in the example below is the most exquisite configuration of all. Look at the grace, proportions, feminity, and beauty of this face:
Jaw shape classification: strong, projecting chin


Flat (with gonial C grade)
It’s a straight jawline that goes from ear lob to chin. Typical of vertical growers. The line is far from being horizontal to the floor line.

Jaw shape classification: down slopping jaw line

Round – convex (almost always with gonial angle of type C)
Jawline appears soft and round. The jawbone is not round, but the very obtuse angle and the soft tissues give this impression.
Jaw shape classification: round jaw line

The concave shape is my favorite. Usually, it follows gonial => B, with chin projection => B.
The gonial and chin are so developed, that they bend the jawline into a concave shape. If you trace the jawline from the gonial and follow the chin, it gives you a kind of exquisite half lying ‘s’ as in the image below (model Sui He).
Jaw shape classification: concave jaw line

Flat jawline (with gonial grade >= B).
The jawline appears completely flat. In contrast with the flat jaw-line with C gonial grade, the jaw plane line is more horizontal to the floor plane.
You can see in this flat jawline with gonial => B, when compared to the above flat with C grade, that there is a whole piece of jaw descending from the earlobe forming the square structure. This descending piece of jaw is not even existing in the C grade with flat jawline. The square jawed face structure is completely different from the more atrophied structures.
Jaw shape classification: flat, straight jaw line


The syntax of the jaw type classification is as such:


Jaw shape classification study sample

This model is a BAflat ( Gonial grade B, chin grade A, jawline flat).


Sometimes it is difficult to classify a jaw shape and the frontier between two classifications is blurry.
In this case, minus (-) and plus (+) signs can be added to the syntax to add some nuances.


B+A- means :

  • B+: a gonial angle that can’t qualify for the A grade because not perfectly square but almost
  • A-: a chin that is almost an A byt very slightly receding behind the chin projection line. An A+ would be an exceptionally projecting chin.

Note that the A+ gonial grade hasn’t ever been documented yet so it can’t be used: it would involve an acute gonial angle which I never observed: ‘A’ is the squarest possible qualification for a gonial angle to this day.


  • Cheekbones width and shapes, frontal gonial angles appearances are not evaluated by this classification, but usually, the profile shape of the lower jaw is indicative of the frontal configuration.
  • An additional jaw classification criteria could be added: the relative size of the jaw. Some women simply have larger facial structures than other women. This has no relation to the jaw shape, although the square jaw type is usually bigger than other types. This is difficult to evaluate and can’t be evaluated without comparison between several faces. Criterions could be ‘small’, ‘medium’ and ‘big’. I may specify this in my classifications when I was able to make evaluative comparisons.
  • It’s difficult to make perfect evaluation just from pictures.
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