Semispinalis refers to a muscle that plays a critical role in maintaining spinal position. It runs from the thoracic to the cervical region and provides support to the vertebral column. There are several synonyms used to describe this muscle, such as the semispinalis capitis, semispinalis cervicis, semispinalis thoracis, and semispinalis dorsi. Other terms used interchangeably with semispinalis include the half-spanning muscle and the half-arrow-shaped muscle. These synonyms exist because the semispinalis muscle is complex, with several sections that can be distinguished based on their trajectory and insertion points in the spinal column. Regardless, this muscle serves a vital function in stabilizing the spine and allowing us to perform everyday activities.