Variations of the rectus capitis posterior muscles: a case report.

Duplication, accessory slips, and division of the rectus capitis posterior muscles are rare anatomical variations. Here we report a case of unilateral doubling of rectus capitis posterior major, and doubling of rectus capitis posterior minor with an accessory slip originating from the spinous process of the second cervical vertebra. The gross anatomical characteristics, clinical significance, and relationship of suboccipital musculature to the cervical myodural bridge is discussed in this report. Knowledge of rectus capitis posterior muscle variations may be of interest to clinicians practicing surgical approaches to the posterior cervical region due to the close proximity of the variations to typical muscular and neurovascular structures of the suboccipital region and potential association with the cervical myodural bridge.