Anomalous insertion of the splenius muscle in a dog

The splenius muscle in the dog is a triangular muscle extending from the third thoracic vertebra to the skull. It inserts on the nuchal line of the occipital bone and the mastoid part of the temporal bone and occasionally it also sends a strong serration to the transverse process of the axis. Here we describe a new, anomalous insertion of both the left and right splenius muscles in one young adult dog routinely prepared for anatomical dissection. In this dog, a group of muscle fibres diverged ventrolaterally from both the right and left splenial muscles to be inserted at the end of the transverse processes of the third cervical vertebra. This anomalous insertion of the splenius muscle corresponds to the splenius cervicis muscle present in other species.