The soft tissues that envelop and support your spine make up an intricate network of muscles. With the help of your body's abdominal muscles, this network helps to keep your body stabilized and upright, and allows it to bend and flex. The types of muscles that support your spine include: Extensors - These are composed of back and gluteal muscles. These muscles help keep your back straight, assist in efforts involving lifting, and moving your thigh away from the body. Flexors - These are your abdominal and iliopsoas muscle, which support the spine from the front. They also control the arch of your lower back and move the thigh in toward the body. Obliques (also called rotators) - These "side" muscles stabilize your spine when you are standing upright, and help rotate your spine and maintain proper posture and spinal curvature.