Table 3.

Angles (°) calculated between the average measured muscle fiber orientations in adjacent muscle layers.

Region	Layers	Rat (°)	Human (Urquhart et al., 2005) (°)
Upper	EO–IO	85	83
	IO–TrA	51	51
Middle	EO–IO	63	86
	IO–TrA	60	48
Lower	EO–IO	85	n/a
	IO–TrA	42	21

Rat data from current study; human data from Urquhart et al. (2005). Angle between the external oblique (EO) and internal oblique (IO) in human is not applicable (n/a) because the EO muscle does not traverse inferior to the anterior superior iliac spine, where the lower region is defined.

TrA, transversus abdominis.