The spinalis cervicis and capitis muscles are small components of the erector spinae group. These muscles are highly variable, and when present, they are typically asymmetric and often fused with other muscles. Herein, we provide a description of our dissection of a well-developed and unilateral discrete spinalis capitis muscle. This muscle arose from the ligamentum nuchae and attached superiorly along the inferiorly nuchal line. While this muscle is infrequent, it is positioned to cause unique patterns of somatic dysfunction and may play a role in the development of cervical and/or occipital headaches. Such a muscle should therefore be of unique interest to osteopathic physicians.
