The spinalis is a muscle located in the back, part of the erector spinae group. It runs along the spine and helps maintain an upright posture. The spinalis is divided into three sections: spinalis thoracis, spinalis cervicis, and spinalis capitis, each corresponding to different regions of the spine. This muscle plays a crucial role in extending the vertebral column and assisting with lateral flexion. Strengthening the spinalis can improve overall back stability and reduce the risk of injury, making it important for activities that involve lifting or bending.