ERECTOR SPINAE MUSCLE: ORIGIN, FUNCTIONS, SYNDROMES - ANATOMY AND PHYSIOLOGY - 2025

The erector spinae muscle comprises a complex group of muscles, accompanied by tendons. All this is covered by a special connective tissue. This functional complex covers an important part of the back, mainly covering the lumbar, thoracic and cervical areas.

They are located in the middle area of ​​the intrinsic muscles of the back. They have fascicles that run vertically along the spinal column. Each fascicle joins a structure, such as: skull, cervical, thoracic and lumbar vertebrae as well as at the level of the sacrum and ilium.

Graphic representation of the muscles that make up the erector spine. Source: Henry Vandyke Carter. Edited image.

The complex group of erectors spinae is made up of three muscles, called iliocostal, longisimo and spinous. These muscles are paired, that is, they are located on each side of the spinal column, specifically in the groove formed between the angles of the ribs and the spinous processes.

The erector muscle group is covered by a layer of connective tissue, called the thoracolumbar fascia, which encompasses the thoracic and lumbar region, while the cervical area is covered by the nuchal ligament.

Among the functions performed by this group of muscles and ligaments is to keep the spine in a straight or upright position, being called for this reason the extensor muscle of the spine. On the other hand, the spine is not a rigid structure, therefore, the set of muscles allows flexion movement.

characteristics

The erector spinae muscle was known for a long time as the sacrospinal muscle, a term currently in disuse. Today it is known as the erector spinae and is sometimes called the extensor spinae, due to its function.

However, it is not a single muscle, therefore, it is considered a very important muscle complex. This is in the middle part of the muscle mass that is located on the back of the trunk.

Below the erector spinae muscle are the following muscles: intertransverse, multifid, rotator, and interspinous. While, above this are: the trapezius, the rhomboids, the latissimus dorsi, the serratus posterior, the quadratus lumbar and the angular shoulder blade.

- Erector spinae muscles

The erector spinae group is made up of three muscles that are paired. These are located symmetrically on each side of the spine vertically. From the bottom up it can be said that the muscle complex extends from the pelvis to the skull. The muscle looks like a thick, broad band.

There are three muscles and they are called: spinous, long and iliocostal.

Thorny

It is located right next to the spine (medial line of the body).

Very long

It is located in the middle, between the spinous muscle and the iliocostalis (intermediate line).

Iliocostal

It is the outermost of the three and the furthest from the spine (lateral line of the body). It is divided into three regions according to the site where its fibers are inserted: lumbar, thoracic and cervical iliocostal.

- Division

It has already been mentioned that the large muscle complex comprises 3 muscles, but there are also ligaments and the thoracolumbar fascia. Therefore, the whole of this structure is divided into zones.

Cranial cervical region

The spinous muscle and the longis muscle participate in this region. These cover the base of the skull, which in turn is covered by the nuchal ligament. Some authors call this part the erector cervical spine muscle.

Thoracic region

All three muscles participate in this area: spinous, longus and iliocostal. They are seen as 3 pillars (from T12 to L1). The fibers of these muscles are thicker towards the base and finer towards their cusp. This area is also known as the erector spinae muscle.

Lumbar region

In this part, the separation of the three muscles is not distinguished, therefore, it appears as a single thick muscle mass. This area is also called the erector lumbar spine muscle.

Sacral region

This region is basically covered by much finer tendons or ligaments, culminating in a point. This part the structure is finer or narrower. It corresponds to the common site of origin of the erector spinae muscle complex.

Origin and insertion

Lumbar or lower part

Its origin occurs at the level of the aponeurosis of the muscle under study. It corresponds to the common origin of the erector spinae muscle. This area has several insertion sites that are: iliac crest (upper third), sacrum (posterior part), spinous processes of the lumbar region and the sacroiliac ligaments.

Thoracic or middle part

In this area the 3 muscles are inserted, serving the spinous processes as the attachment site for the spinous muscle fibers. Meanwhile, the transverse processes serve as a site of attachment for the muscle fibers of the longis. While, in the ribs the thorny is inserted.

Cervical or upper part

In this area, the spinous processes also serve as an attachment site for the muscle fibers of the spinous bone, but it also inserts at the base of the occiput.

Likewise, the transverse processes continue to serve as an attachment site for the muscle fibers of the longus muscle and it also inserts into the mastoid process of the temporal bone.

Innervation

The complex group of muscles is innervated by the spinal nerves, specifically receiving lateral branches that come from the posterior branch.

Irrigation

Because it is a large muscle and has a long history, it is irrigated by many blood vessels depending on the area.

In the cervical area, it is supplied by the superficial and deep descending branches of the occipital artery, the transverse cervical artery, the deep cervical artery and the vertebral artery.

The dorsal or thoracic area is supplied by the dorsal branches of the superior, posterior, and subcostal intercostal arteries.

And the lower or lumbosacral part is nourished by the dorsal branches of the lateral and middle sacral arteries.

Venous return is performed under the same pattern. Changing the word artery for vein.

Features

Its bilateral action is to extend both the neck and the spinal column, being essential to maintain a totally straight or upright position. In this sense, its action is concentric.

In its unilateral action, it performs flexor function, allowing the movement of the spine and neck to one side or the other, depending on the muscle that is acting (right and left). The movement is executed to the same side of the muscle that is in action.

It also participates in the forward movement of the spine, where the erector spinae muscle plays a fundamental role in controlling descent, acting eccentrically.

Syndromes: back pain

Back pain is a very common ailment and most cases are muscular in origin. Pain can occur from muscle stretching or spasms, and trigger points may appear.

Strains

The muscle fibers of the erector spinae can tear or stretch due to an excessively poorly balanced load on the back. This causes the muscles to become overloaded.

Spasms

When the body is not warmed up before exercising certain exercises, cramps can occur, which is characterized by muscle contractions that are usually painful, affecting the deterioration of its function.

Trigger points

The muscle can suffer contractures at any given time, due to poor posture, muscle weakness, weight overload, among others. Trigger points cause pain, generally occurring at the lumbar level (unilateral), but can radiate towards the gluteal area.

Treatment

To relieve this muscle, it is recommended to rest the first days of pain, it is also favorable to place heat in the affected area to increase blood flow.

Likewise, it is advisable to perform exercises, especially stretching, as well as to avoid being constantly in the same posture, either sitting or standing. Finally, it is useful to perform physiotherapy (massage, exercises, electrotherapy, etc.)

In case of acute pain that does not stop with the aforementioned, there is a surgical alternative that eliminates the pain at its roots. This is accomplished by blocking the erector lumbar spine plane.

Palpation

To palpate the muscle, you must first locate it. A quick and easy way to do this is to tell the patient to lie on their stomach and then try moving their head, pelvis, and arms back. There you can see how the muscles tense on each side of the spine. Once located, they can be palpated and massaged.

Strengthening exercises

There are a variety of positions used in yoga that help strengthen this muscle. See the following figure.

Yoga positions that strengthen the erector spinae muscle. Source: image taken from: Costa A. Erector of the column. Synthesis Yoga Teacher Training School. Available at: cuerpomenteyespiritu.es. Edited image.

Related disorders

Adolescent idiopathic scoliosis

Patients with this disorder have a deviated spine, which may be painless or painful. Pain is associated with chronic myofascial trigger points. One of the muscles most affected in this disorder is the erector spine muscle.

References

1. Costa A. Erector spine. Synthesis Yoga Teacher Training School. Available at: cuerpomenteyespiritu.es
2. "Erector spinae muscle" Wikipedia, The Free Encyclopedia. 18 Nov 2017, 00:59 UTC. 29 Sep 2019, 01:28 en.wikipedia.org
3. Gala P. Prevalence of Myofascial Trigger Points in Adolescent Idiopathic Scoliosis. Number of cases. 2012, graduate work to qualify for the title of physiotherapist. University of Alcalá. Available at: ebuah.uah.es
4. Lumbar erector spinae plane block: successful control of acute pain after lumbar spine surgery. A clinical case Spanish Journal of Anesthesiology and Resuscitation, 2019 66 (3) 167-171. Available at: Elsevier.
5. Gonçalves M, Barbosa F. Analysis of parameters of force and resistance of two erector muscles of the Lombard spine during the performance of isometric exercise in different levels of effort. Rev Bras Med 2005; 11 (2): 109-114. Available from:.scielo.