Which measurement is critical for fitting the shoulders properly in a shirt pattern?

The measurement that is critical for fitting the shoulders properly in a shirt pattern is shoulder width. This measurement directly affects how the shirt will fit across the shoulders, ensuring that it accommodates the wearer's body shape and allows for comfortable movement. Proper shoulder width helps in aligning the seam that connects the sleeves to the body of the shirt, which is essential for the overall aesthetics and functionality of the garment.

When the shoulder width is accurately measured and accounted for in the pattern, it ensures that the shirt sits well on the wearer’s body without being too tight or too loose. This can significantly enhance both comfort and style. Other measurements like chest, bust, and neck circumference do contribute to the fit of a shirt but do not specifically address the fit across the shoulders, making shoulder width the most relevant measurement in this case.