A - Length
Place the end of a measuring tape beside the collar at the top of the garment (high point shoulder). Pull the tape to the bottom of the item.
B - Width
Place the end of a measuring tape at one side of the chest area and pull the tape across to the other side of the product.
C - Sleeve length
Place the end of a measuring tape at the center back of the collar, then pull the tape along the top seam of the sleeve. When you get to the shoulder hold the tape in place at the shoulder and continue to pull down the sleeve until you reach the hem of the sleeve.