Several studies have come up with different external landmarks for the transverse sinus -the point of insertion of semispinalis capitis muscle, the superior nuchal line (SNL) etc.
Tubbs R.S et al  have demonstrated that the most accurate external landmark that can be estimated in reliably predicting the internal placement of proximal transverse sinus is the point of insertion of semispinalis capitis muscle (MSC).
In the spot method, 3 to 5 locations (3.0 cm in diameter) for longissimus thoracis muscle, 3 locations 2.5 cm in diameter for trapezius muscle, 2 locations 3.0 cm in diameter for semispinalis dorsi muscle and 1 location 2.5 cm in diameter for semispinalis capitis muscle were selected rapidly on the monitor (Figure 2).
The areas of the longissimus thoracis muscle in particular were relatively strongly correlated with semispinalis dorsi muscle (r = 0.81), semispinalis capitis muscle (r = 0.72) and trapezius muscle (r = 0.63) (p > 0.01).
In the overall trace method for marbling, the marbling in the longissimus thoracis muscle was relatively strongly correlated with semispinalis dorsi muscle (r = 0.73), semispinalis capitis muscle (r = 0.69) and trapezius muscle (r = 0.70) (p > 0.01).
Photographs of the loin cuts including longissimus thoracis, trapezius, semispinalis dorsi and semispinalis capitis muscles were taken with a scale using a digital camera (C-3100, Olympus Co., Tokyo, Japan) on the carcasses at meat markets.