Paraspinal muscles: anatomy and function


The paraspinal muscles are the muscles in the back that "work." When they work, the result is obvious spinal movement. They run down the back and spine and help move the spine in extension, rotation, and lateral flexion.

But first, let's clarify our terms. The technical name for paraspinal bones is erector spinae; It goes without saying that many people struggle with pronunciation. This is probably why the words "paraspinal muscles" and the term "paraspinal muscles" are commonly used to refer to this important group of back muscles.


The paraspinal bones are a set of three muscles that occupy the so-called middle layer of the internal muscles of the back. As the name suggests, the middle layer is found above the deep layer and below the surface layer .

The three layers of the inner back muscles lie below two more groups of superficial back muscles, which together make up the outer muscles of the back.

The paravertebral muscles are found to the left and right of the spine and are made up of three groups. These include :

  • Iliokostalis
  • Longissimus
  • Spinalis

These muscle groups attach to various parts of the cervical, thoracic, and lumbar spine. They usually extend from the spinous or transverse process of a vertebra to the spinous or transverse process of the vertebra one, two, or three levels below.

The paraspinal bones are innervated by nerves from the dorsal branches of the first cervical nerve to the fifth lumbar nerve, depending on the level of the muscle.

Nicholas Coe / EyeEm / Getty Images


The job of the paraspinal muscles is to stretch the spine and bend it in the same direction as the contracting paraspinal muscle. Many people equate the spinal extension movement with the arching of the back, which can be a good way to think about this when describing or attempting to perform the movement.

The contraction of the paraspinal muscles also serves to "test" the work of the abdominal muscles. In other words, the abdominal muscles, especially the rectus abdominis muscle, flex the torso forward.

When this movement occurs, the eccentric contraction of the paraspinal bones as the muscle lengthens prevents the torso from flexing too quickly and too far forward.

The abdominal and paraspinal muscles work together to help maintain an upright posture through the same mechanism. If one is affected, the resulting imbalance will affect the other, increasing the risk of chronic pain and injury .

Chronic back pain is often associated with the paraspinal muscles. Causes include poor posture (causing direct muscle tension), muscle tension , and muscle atrophy (in which reduced muscle mass weakens the support of the spine).

Components (edit)

The paraspinal muscles run the length of the spine from the skull to the pelvis. Although all three start in the same place, certain areas in the lower part of the spine, and all have lumbar, thoracic, and cervical portions, their muscle fibers attach to different aspects of the vertebrae and ribs of the spine.

The three muscles that make up the middle layer of the internal muscles of the back are the iliocostalis, longus, and thoracic muscles .

Iliocosteal muscle

The iliocostal muscle is the most lateral or external of the three paraspinal muscles. It originates from a broad tendon on the dorsum of the hip bones, the dorsum of the sacrum, the sacroiliac ligaments, and the spinous processes of the lower lumbar vertebra. This includes the ligaments that connect these processes to each other.

The Iliocostalis group is largely responsible for the extension, flexion, and rotation of the spine, allowing us to lean back and to the sides and twist the spine.

The iliac bone is divided into three distinct parts :

  • The lumbar iliac muscle is moved upward from the lower pelvis and sacrum to attach to the lower border of the lower six or seven ribs using tendons that branch off from the baseline.
  • The sternum is also attached to the ribs, but this is the top of the top six ribs. This part also attaches to the posterior part of the transverse processes of the seventh cervical vertebra. The word cervical refers to the neck.
  • The cervical part of the iliac muscle is attached to the posterior part of the transverse processes of the fourth to seventh cervical vertebrae.

Longer muscle

Like the ilioiliac muscle, the longissimus derives from a broad tendon on the dorsum of the hip bones, the posterior part of the sacrum, the sacroiliac ligaments, and the spinous processes of the lower lumbar vertebra.

It also includes the ligaments that connect these processes to each other. The longus muscle is located between the iliocostal and dorsal muscles.

Like the ilium, the longus muscle has three parts. But instead of the lumbar, thoracic and cervical parts, this muscle has the pectoral, cervical and cranial parts, each of which performs certain functions :

  • The thoracic part is attached to the ends of the transverse processes of all the thoracic vertebrae and the muscular branches to the lower nine or ten ribs.
  • The cervical longissimus is attached to the transverse processes of the second to sixth cervical vertebrae.
  • The skull is attached to a bony protrusion known as the mastoid process, which is located at the back of the skull, just behind the lower ear.

Spinal muscle

Like the iliocostal and longus muscles, the spine is derived from a broad tendon on the dorsum of the hip bones, the posterior part of the sacrum, the sacroiliac ligaments, and the spinous processes of the lower lumbar vertebrae, including the ligaments that connect these processes. each other.

Of the three paraspinal muscles, the spinal muscle is the closest to the midline. It also consists of three parts :

  • The thoracic part attaches to the spinous processes of the four to eight (may vary) upper thoracic vertebrae.
  • The cervical portion attaches to the spinous process of the second cervical vertebra, called the shaft, and sometimes to the spinous processes of one or two vertebrae below it. It originates from the dorsal ligament from C4 to C6 and the spinous processes from C7 to T2.
  • The head is often less distinguishable from the neck, but functions independently to help rotate, support, tilt, and move the head.

Related conditions

Injuries to the back or spine can cause pain and limit the function of the parapinal organs. This can cause symptoms such as:

  • Back pain
  • Muscle cramps in the back
  • Difficulty leaning forward, sideways, or backward
  • Difficulty maintaining correct posture.

If you have any of these symptoms, it is recommended that you visit your doctor. He or she can verify everything and make a diagnosis. Then the correct treatment can begin.


If you have injured the paraspinal muscles of your back, you may be advised to see a physical therapist or specialist. Keep in mind that you should check with your doctor first to make sure rehab is safe for you. Most parapinal problems respond well to light stretching and strengthening exercises.

Exercises include:

These exercises are a combination of stretching and strengthening and can help balance the paraspinal muscles in your back.

Posture training may also be recommended to keep the paraspinal muscles in good condition. By maintaining proper posture, you can keep your parapinal organs functioning normally without overloading them. Striving to be posture conscious and having strong but flexible paraspinal muscles will help you move without pain.

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