Figure 23. A in Functional morphology of neck musculature in the Tyrannosauridae (Dinosauria, Theropoda) as determined via a hierarchical inferential approach

Figure 23. A, topological appearance of m. rectus capitis ventralis (anterior muscles) and m. iliocostalis cervicis (posteroventrally originating muscles) on anterior axial skeleton of Tyrannosaurus rex (BHI 3033), ventral view. The moment arm for lateral flexion by m. iliocostalis cervicis is superimposed. B, m. r.c.v.: origins of m. rectus capitis ventralis from ventral spinous processes of Tyrannosaurus rex (BHI 3033) with arrow showing course of the muscle. m. il. cerv.: origin from ventral centra and insertions onto ventral fascia of cervical ribs of m. iliocostalis cervicis, with arrow showing course of the muscle. C, insertion of m. rectus capitis ventralis onto basioccipital of Daspletosaurus torosus (CMN 8506; the specimen is incomplete and the image partly mirrored), showing moment arms. Because the tyrannosaurid occiput slopes anteroventrally, the ventroflexion moment arm is somewhat longer than depicted in this view. D, strength of functional inference for head ventroflexion by m. rectus capitis ventralis in Tyrannosaurus rex. E, strength of functional inference for neck lateroflexion by m. iliocostalis cervicis of Tyrannosaurus rex.