The chest with an AP diameter approximately equal to its transverse diameter is most commonly described as which chest shape seen in older adults?

• A. Barrel chest
• B. Pectus carinatum
• C. Pectus excavatum
• D. Funnel chest

Answer: (A)

Barrel-shaped chest describes a front-to-back (AP) diameter that is increased so it closely matches the side-to-side (transverse) diameter, giving a round, widened appearance. This pattern is commonly seen in older adults due to aging-related changes in the chest wall and lungs, such as decreased elastic recoil and gradual hyperinflation, which roughen the chest’s contour and make the AP dimension more prominent. So describing a chest where the AP and transverse diameters are roughly equal fits this barrel shape.

Pectus carinatum is a protruding sternum (pigeon chest)—a fixed deformity, not the aging-related barrel shape. Pectus excavatum (funnel chest) is a sunken sternum, another distinct deformity. These do not describe the barrel-like, increased AP diameter seen with aging.