underbust

Underbust refers to the area of the torso directly beneath the breasts. It is a common anatomical landmark used in garment construction, sizing, and descriptive anatomy, and it helps define the silhouette of the upper torso.

Anatomy and relationship: The underbust line roughly marks the lower boundary of the thoracic cage and the upper abdomen. It varies with body shape, posture, and breathing. The measurement taken at this level—often called the underbust circumference—is distinct from the bust measurement taken around the fullest part of the breasts.

Measurement: To measure the underbust, place a flexible tape measure around the torso directly under the breasts, keeping it horizontal and snug but not tight. Take the measurement at the end of a normal exhale or at a comfortable resting state. Record the measurement in centimeters or inches. Proper technique helps ensure consistency for sizing and garment fit.

Uses in clothing and design: The underbust measurement is commonly used to determine band sizes in bra sizing and to guide the fit of corsets, bustier-style garments, and fitted bodices. Designers reference the underbust position when shaping the torso and determining garment length and support features.

Other contexts: In medical, fitness, and cosmetic descriptions, the underbust serves as a reference point for assessments, imaging, and planning. While the emphasis and methods may vary by region and purpose, the underbust remains a standard landmark for fitting and description.