FIGURE 3. Position vectors for M in Craniocervical feeding dynamics of Tyrannosaurus rex

FIGURE 3. Position vectors for M. transversospinalis cervicis (M. trans. cerv.), inserting on the epipophyses of C2 (A, B, C), C3 (D, E, F), and C4 (G, H, I) of Tyrannosaurus rex (AMNH 5027; skeletal drawings modified from Paul 1988), and of M. splenius capitis from the axis to the parietals (G, H, I). Note that via points proximal to insertions act as geometric ''origins'' of pull. Insertions and via points through which tendons ran are labeled in A, D, and G. Neutral/slightly elevated, dorsiflexed, and ventroflexed postures are shown from left to right in each sequence. The lateral z components (A, D, and G: dorsal views) were constant for calculating lateral flexion resultants in all postures, whereas x (anteroposterior) and y (dorsoventral) components varied with posture.