Fig. 7.

Schematic drawing illustrating the structural features of muscles that originate on the vertebral column and insert on the skull. (a) The line drawing of biventer cervicis (BC) shows its compartmentalized structure due to its tendinous inscriptions, which cross the muscle fascicles obliquely, and divide this muscle into five divisions. (b) An exploded view of BC when compartments are separated from one another along the tendinous inscriptions. Unlike the simple structure of the cranial compartments, the caudal compartments have a more complex organization, with a wide variety of fascicle lengths coexisting within them. (c) The organization of muscle heads of complexus (COMP) demonstrates that the two heads, which originate from the articular processes of C₃ and C₄, could not be easily separated in all dogs.