Previously undescribed variant muscle connecting longissimus and semispinalis capitis muscles.

Thelongissimus capitis and the semispinalis capitis both function to bilaterally extend and unilaterally rotate the head. Typically, these muscles are distinct with origins and insertions at independent locations along the vertebral column. During a routine cadaveric dissection, an unusual muscle strip was identified between the longissimus capitis andsemispinalis capitismuscles on the left, posterior neck. This anatomical variation may have developed due to an incomplete or abnormal columnar segregation during gestation. The presence of this muscle strip contributes to previous case reports that have identified abnormal musculature between and along the longissimus and semispinalis muscles. Awareness of this muscular variant should be kept in mind by clinicians and surgeons who treat/operate this area of the body.