Also known as extensor spinae or sacrospinalis, the erector spinae refers to a muscle group occurring at the back. It bends the spine in such a way that the chest projects outwards and the head moves backwards, thereby extending the vertebral column. The muscle is actually made up of 3 muscle columns known as the Iliocostalis, Longissimus, and Spinalis, each of which extend from the skull’s lower back down to the pelvis and run parallel on both the outer sides of the vertebra.
The erector spinae offers resistance which in turn helps controlling the action of forward bending motion at the waist and also has strong extensors that facilitate the springing of the back once again to the erect position. When touching the floor with the fingertips, i.e., at the time of full flexion, the muscles of the erector spinae are relaxed and the accompanying strain is fully borne by the back ligaments. However, when this movement is reversed, then the erector spinae muscles along with the muscles of the hamstring and the buttocks (gluteus maximus) is mainly responsible for straightening of the spine and lengthening of the back, as well as for more precise motions such as sideways motion of the head and neck extension.
Erector Spinae: Structure and components
The erector spinae is not only a single muscle, but a bunch of tendons and muscles. It occurs as a pair in the vertebral column’s side groove and extends almost vertically across the thoracic, lumbar, and cervical areas. In the thoracic and lumbar regions, the muscle is enclosed by the thoracolumbar fascia, while the nuchal ligament covers it in the cervical area.
The large tendinous and muscular mass of the erector spinae differ in structure and size at varied sections of the vertebral column. It is constricted and pointy in the sacral area and its origin mainly features tendinous structure. It is bigger at the lumbar area and develops a fleshy thick mass. Then as it goes upwards, it sub-divides into 3 columns which slowly reduce in size while ascending to get interleaved into the ribs and vertebrae.
The erector spinae commences from the front surface of a thick and broad tendon. It is connected to the lumbar spinous processes and the supraspinous ligament and the 11th and 12th thoracic vertebrae, the sacrum’s medial crest, to the posterior section of the iliac crests’ inner lip, and to the sacrum’s lateral crests where the muscle combines with the back sacroiliac ligaments and sacrotuberous. Some of the fibers of the erector spinae are continuous with the origin fibers of the buttocks/gluteus maximus.
The muscular fibers develop into a fleshy big mass that separates in the superior lumbar area into 3 columns, i.e., Iliocostalis, Longissimus, and Spinalis. Each of them are made of 3 parts, superior and inferior, as discussed below:
- Longissimus dorsi muscle: It is the longest muscle at the back and consists of 3 different parts, i.e., the cervicis, the capitis, and the thoracis.
- The cervicis muscles help maintain the erect position of the cervical spine and bend the upper part of the neck. Its originates from the narrow tendons of the top four’s lateral surface, while its insertion points are from cervical vertebra 2 to 6’s lateral surface.
- The capitis muscles help maintain erect position of the head and rotate in the side of muscle contraction. Its insertion point is the skull’s mastoid process, while its origin joining points are from top four’s lateral surface.
- The thoracis muscles help maintain erect position of the spine, facilitate sideways and backward bending motion, and pull down the ribs to assist breathing. Its origin point is from the sacrum, the lumbar vertebrae’s spinous processes, and the last thoracic vertebra’s transverse process, and its 2 insertion points are the lumbar vertebrae’s the transverse processes, and laterally the ribs (lower 9 or 10), erector spinae aponeurosis, and the thoracic vertebrae’s costal processes.
- Iliocostal muscles/Iliocostalis muscle: Of all the muscles that make up the erector spinae, the Iliocostalis muscle is farthest from the vertebra. It mainly helps laterally flex and extend the vertebral column, maintain erect posture, and bend the vertebral column towards the same side. Its origin connection area is the lumbosacral fascia, the cervicis- ribs three to six, and thoracis- the lower six ribs. The points of insertion attachment are the angles of the thoracis and lumborum, i.e., ribs seven to 12 and transverse processes of cervicis, i.e., cervical C6 to C4.
- The spinalis muscles: Of all the erector spinae muscles, it is the nearest to the vertebra and is made of 2 muscles, i.e. the thoracis and the cervicis.
- The origin points of the spinalis thoracis are from the lumbosacral fascia’s inner section as well as from T11 to T12’s spinous processes. Most of the insertion attachment points are spinous processes of T2 to T8. These muscles work in tandem with the spinalis cervicis muscles to laterally flex and extend the vertebral column.
- The origin points of the spinalis cervicis are from the inferior ligamentum nuchae, i.e., C6 or C7’s spinous processes. The insertion attachment point is the axis’ spinous process. These muscles work in tandem with the spinalis thoracis muscles to laterally flex and extend the vertebral column.
Exercises for erector spinae muscles
Some exercises for the erector spinae muscles are listed below:
- People who have access to a gym can go0 for exercises on the seated row or lat pull-down machines.
- Exercise balls can help stretch the erector spine muscles. Rest the waist on the ball and the wide-set feet on the floor and place the hands behind the head. Now, lift the body using the back muscles, hold for a second, and then back down on the ball.
- Use handheld weights to exercise the back muscles. A good example is a bent over row. Hold a weight in one hand, bend down at the hip, keep the back straight, and let the hands hang to the floor. Now, pull up the elbows towards the ceiling while simultaneously pushing the shoulders towards the center of the back. Repeat 10 to 15 times, switch the weight to the other hand and repeat with other hand.
- Bird dog position exercise, lateral flexion stretch, knee-to-chest stretch, and back and front fasciae stretch are some erector spinae exercises that can be done without any equipment.