The psychologist William Sheldon divided body types into categories. He said that most people fit into one of three categories: ectomorph, mesomorph or endomorph. Many people are mostly one category with a few traits of one other.
Mesomorphs tend to have squarish, well-defined heads with thick hair. Endomorph heads are more rounded, and the hair is usually fine.
Shoulders and Chest
Mesomorphs display broad shoulders and chests, with good posture. An endomorph may have broad shoulders and a barrel chest, but the muscles may be less defined.
The waist of a mesomorph is proportionately small, presenting an hourglass figure in women. Endomorphs tend to carry weight in the middle, giving a rounded appearance.
The hands and feet of the mesomorph are proportionate, with medium-size digits, and the muscles are well-defined. Endomorphs often have small hands and feet in comparison with their height.
In general, the mesomorph is short to medium in height with an athletic build that adds muscle and burns fat easily. The endomorph is usually medium to tall and tends to add muscle easily but has a hard time losing fat.