Neck width ratio

A neck that narrows beneath the jaw corners leaves a visible step inward on each side. This can make the jaw stand out even when its width is modest. As neck width approaches jaw width, the outline becomes more continuous and the corners may appear less distinct.

The denominator is the jaw, so this comparison concerns the transition immediately below the face. Broad jaw corners can create strong separation above a neck of ordinary width. A narrower jaw above that same neck can produce a much higher ratio and less visible separation.

When the cheeks, jaw and neck all retain substantial breadth, the lower outline can look broad throughout. A high neck-to-jaw ratio then continues the width already present in the face. With a narrow jaw, the same neck width creates more contrast: the face narrows below the cheeks, but the outline widens or stops narrowing where the neck begins.

A low ratio can also occur in different settings. Broad jaw corners above a narrow neck stand apart clearly, and a broad chin can complete a square lower face above that separation. Narrow corners above an even narrower neck create a finer outline overall. Their proportions may match while the impression of size differs.

Neck width changes along its height. The sides may turn inward just beneath the jaw and broaden again towards the shoulders, or follow a straighter path. Necks with the same width at the marked level can therefore have different amounts of visible narrowing above and below it.

Gulsever and colleagues tested changes to this concavity in male and female silhouettes and found preferences among the contour options. Their measurement described the angle of an hourglass-like shape rather than a neck-to-jaw width fraction.

The side-view boundary beneath the chin adds different information. Clear separation at the jaw corners can coexist with a softer chin-to-neck contour in profile. Looking at both views distinguishes the lateral outline from the area directly under the chin.

Neck muscle and other soft tissues contribute to its visible width. Shoulder breadth also affects how large the head and neck appear together, which is why a tight facial crop can give a different impression from a head-and-shoulders portrait. A width measurement alone cannot separate muscle from other tissue.

Posture can change the outline immediately. Raised shoulders, a turned head or a flexed neck alter the visible contour and may change where its width is marked. Use similar head and shoulder positions when comparing photographs, and measure at the same neck level each time.

The 0.90–1.05 reference describes neck width close to jaw-corner width. This tends to give a more continuous outline than a much narrower neck, although an inward curve beneath the corners can still create definition. A lower ratio makes that lateral step larger, especially beneath a broad jaw.

The contour experiment found preferences for particular shapes below the jaw, but it did not test this reference interval.