Shoulder width, also known as "acromion width", refers to the straight line distance between the left and right acromion points.
maximum shoulder breadth
The maximum shoulder width, or "maximum shoulder width", is the horizontal straight-line distance between the most prominent parts of the upper arm on the deltoid muscle (including arm thickness, but also including straight-line distance).
Span shoulder
The total shoulder width refers to the arc length of the back from the left shoulder end to the right shoulder end through the midpoint of the back neck (the seventh cervical vertebra point); Or defined as the natural droop of the subject's arm, measure the horizontal arc length between the left and right acromion points.
Xiao Hai compiled an excerpt from the average shoulder width of adults for your reference: