ILIOCOSTAL MUSCLE: CHARACTERISTICS, ORIGIN, FUNCTION, PATHOLOGIES - ANATOMY AND PHYSIOLOGY - 2025

The iliocostal muscle, together with the spinous and longis muscle, make up the muscular complex called the erector spine. The complete muscle complex is located on the posterior and medial aspect of the trunk, on each side of the spine. The iliocostalis is the outermost of the three muscles.

Its name comes from the Latin musculus iliocostalis. It is divided into three portions according to the area through which it passes. The muscle begins at the lumbar level and its fibers go up the dorsal area, finally reaching the cervical region.

Graphic representation of the iliocostalis muscle. Source: modified by Uwe Gille. Edited image.

Its function is not different from that of the aforementioned muscular complex (the erector spine), as it works synergistically with the spinous and the longis to keep the spine in an upright position and for its lateral movements.

Frequently, the iliocostal muscle is affected by the appearance of trigger points that generate pain at the lumbar level, causing a condition often called lumbago.

characteristics

It is a long, thin, superficial and even muscle. As this muscle encompasses the entire spinal column, it has been divided into three portions that are: lumbar iliocostalis (iliocostalis lumborum), dorsal iliocostalis (iliocostalis dorsi) and cervical iliocostalis (iliocostalis cervicis). As described, its fibers are on the rise.

In the lumbar area, the muscle is condensed into a large muscle mass next to the spinous and the long.

At the level of the dorsal iliocostalis, the muscle is fully individualized, as is the cervical iliocostalis. The latter is located right next to the longis muscle of the neck, forming part of the posterior and medial neck muscles together with it.

It should be noted that the iliocostal muscle, together with the spinous and longis muscle, make up the erector spine muscle.

The antagonist muscle of the iliocostalis and the erector spinae itself is the rectus abdominis.

Origin

Lumbar portion

The portion corresponding to the lumbar area has its origin in three different anatomical areas.

One part arises in the posterior area of ​​the sacrum (S3), continuing in the posterior third of the iliac crest of the pelvis, touching the sacroiliac joint, and the last one originates from the L4 and L5 lumbar vertebrae, specifically in the thoracolumbar fascia.

The origin of this portion generates 6 muscle fascicles that are used to achieve its posterior insertion.

Dorsal portion

It originates from the flat tendons in the dorsal area of ​​the last 6 ribs. It has 6 muscle fascicles.

Cervical portion

It is born from the third to the sixth rib. It has 4 muscle fascicles.

Insertion

Lumbar portion

This portion is inserted posteriorly and laterally from the sixth rib to the 12th rib. Similarly at the level of the deep layer of the thoraco-lumbar fascia, as well as in the transverse processes from L1 to L2.

Dorsal portion

In this case, it is inserted from rib number 1 to rib number 6 at its lower edge, and from the second to the seventh cervical vertebra at its upper edge.

Cervical portion

It inserts into the processes of the cervical vertebrae number 4, 5 and 6, specifically in the posterior tubercles.

Innervation

The posterior branch of the spinal nerves is in charge of innervating the iliocostal muscle (C1-L8).

Irrigation

The arteries responsible for supplying the iliocostal muscle are the intercostals and the lumbar or subcostals.

Function

The iliocostalis muscle acts in conjunction with the longiscus and the spinous, that is, they work as a single muscle (erector spinal complex) to make it possible to tilt the spine from one side or the other, depending on the muscle that is used. active (right or left).

In the same way, it works synergistically with these muscles to maintain the upright position of the spine, that is, in its extension. In this case it is necessary for both muscles to be activated (right and left).

Related pathologies and disorders

The lumbar and dorsal area of ​​the back in general are areas highly affected by overloads and tensions that can trigger muscle pain at these levels.

Among the muscles that can be affected is the iliocostalis, specifically the dorsal and lumbar area of ​​this. A malfunction of the muscle can cause the appearance of trigger points.

- Trigger points

The most vulnerable areas for the appearance of trigger points are the dorsal region and the lumbar region of the iliocostalis. In general, it does not affect individually, and the longissimo, latissimus dorsi and quadratus lumbar are also involved.

Dorsal region

When the trigger point is located at the upper end of the dorsal iliocostal muscle, the pain produced radiates from the inner part of the shoulder blade to the chest at its lower edge. This pain is easily confused with angina pectoris.

If, on the other hand, the trigger point is located at the level of the lower end of the same muscle portion, the pain radiates in different directions, which are: up, down and to the side.

Lumbar region

The trigger point located at the level of the lumbar iliocostalis causes pain in this region, especially it is concentrated towards the side of the hip and it is possible that it extends towards the gluteus.

- Lumbago

A large part of patients who complain of pain known as lumbago, is due to the presence of trigger points or fibrositis of the iliocostal muscles at the lumbar level.

Sometimes the pain becomes chronic despite having been treated, when this occurs it may be due to a misdiagnosis, since the pain can not only come from the lumbar region, but also from the sacrococcygeal and pelvic area.

That is why, some specialists consider that the lumbar spine should not be seen in isolation, but integrated together with the sacral, coccygeal and pelvic areas, which they call the functional unit.

- Treatment

Trigger points can be eliminated with physiotherapy, for this, various techniques can be used, for example muscle stretching, massages and isometric contraction and relaxation techniques, among others.

References

1. Alí-Morell O, Zurita-Ortega F, Fernández-Estévez B, Padilla-Obispo B, Martínez-Porcel R. Erector Spinae And Scoliosis In A Population With Cerebral Palsy: A Preliminary Study. Coluna / Columna 2018; 17 (1): 14-18. Available from: scielo
2. Santana L, Carvalho P, de Sousa L, Lopes Ana, Araujo A, Azevedo F, et al. Electromyographic analysis of the vertebral extensor muscles during the Biering-Sorensen Test. Motor: educ. fis. 2014; 20 (1): 112-119. Available from: scielo.br
3. Acevedo J., Pérez J. New concept of lumbo-sacral-coccygeal-pelvic functional unit: theoretical bases and repercussion in the clinical and therapeutic analysis of patients with low back pain. Rev. Soc. Esp. Pain, 2016; 23 (5): 260-268. Available at: scielo.isciii.
4. Guiroy A, Landriel F, Zanardi C, et al. “Postoperative paraspinal atrophy. Does boarding matter? " Surgical neurology international, 2018; 9 (4): S91-S96. 2018. Available from: ncbi.nlm.nih.gov/
5. "Iliocostal muscle". Wikipedia, The Free Encyclopedia. 1 Aug 2019, 10:53 UTC. 25 Oct 2019, 22:24