The erector spinae is a group of muscles that runs the length of the back, from the pelvis to the base of the skull. It is the primary muscle group responsible for keeping the spine upright. These muscles are in a near-constant state of contraction throughout the day to stabilize the spine and counteract the force of gravity.
Anatomy of the Erector Spinae
The erector spinae is not a single muscle but a complex bundle of muscles and tendons arranged in three parallel columns on either side of the vertebral column. This intricate structure works collectively to support and move the spine.
The most lateral, or outermost, column is the iliocostalis. This group is subdivided into three parts based on location: the iliocostalis lumborum in the lower back, the iliocostalis thoracis in the mid-back, and the iliocostalis cervicis in the neck. This column connects the ribs and the vertebrae to the pelvis.
The intermediate column, situated between the other two, is the longissimus. As its name suggests, it is the longest of the three columns, extending from the sacrum at the base of the spine up to the skull. It also has three parts—thoracis, cervicis, and capitis—that help to control movements of the back and neck.
The most medial column, closest to the spine, is the spinalis. This is the smallest of the three columns and primarily connects the spinous processes of adjacent vertebrae. It is most prominent in the upper back and neck regions. Together, these three columns form a muscular support system for the entire axial skeleton.
Core Functions
The primary action of the erector spinae muscles is to move the vertebral column. When both sides of the muscle group contract simultaneously, they produce spinal extension. This is the movement of straightening the back from a bent-over position, such as when standing up after tying your shoes, and also allows you to arch your back.
When only one side of the erector spinae group contracts, it results in lateral flexion, or bending the torso to that same side. This action allows for side-to-side movements and contributes to twisting motions of the trunk.
Beyond dynamic movements, the erector spinae plays a constant role in maintaining posture. They provide stability to the spine by steadying it on the pelvis, which is important during activities like walking. This stabilizing function allows the limbs to move from a secure base.
Common Causes of Pain and Injury
Pain in the erector spinae often stems from muscle strain, the tearing or overstretching of muscle fibers. A frequent cause of this strain is improperly lifting heavy objects. Using the back as a lever, rather than the legs, places significant stress on these muscles and can lead to injury.
Poor posture is another contributor to erector spinae pain. Spending long hours sitting, especially while slouching over a desk or phone, forces these muscles into a lengthened and strained position. Over time, this can lead to chronic tightness and weakness as the muscles compensate for weak abdominal and gluteal muscles.
Repetitive activities or sports that involve frequent bending and twisting can also lead to overuse injuries. Without adequate rest, the muscles can become inflamed. Pain can also result from muscle spasms, which are involuntary contractions that occur as a protective mechanism after an injury, causing cramps and a decrease in function.
Strengthening and Stretching
Maintaining the health of the erector spinae involves a balance of strengthening and stretching. Strengthening movements build endurance and stability, while stretching improves flexibility and relieves tension. Before beginning any new exercise program, it is advisable to consult with a healthcare professional.
For strengthening, exercises that target the back extensors are beneficial. The “Superman” exercise is performed by lying face down and lifting the arms and legs off the floor. Another effective exercise is the glute bridge, which involves lying on your back with knees bent and lifting the hips. The “Bird-Dog” exercise is performed on all fours by extending an opposite arm and leg to enhance core stability.
To stretch the erector spinae, gentle forward-bending and rotational movements are effective. The “Cat-Cow” stretch, performed on all fours, involves alternately arching and rounding the back to mobilize the spine. A double knee-to-chest stretch, done while lying on the back, helps release tension in the lower back. A rotational stretch can be done by sitting, crossing one leg over the other, and gently twisting the torso toward the bent knee.