Anatomy of the muscles of the back

The muscles of the back they are in the area of ​​the body trunk that is in the posterior region. We could delimit it between the neck and the pelvis, where the lower limbs already begin. Likewise, the back can be divided into two regions:

  • Thoracic area: it is the upper part of the back, in direct relation with the upper limbs and with the thoracic organs, such as the lungs and the heart.
  • Lumbar area: It is the lower part of the back, under the thorax, linked to the lumbar spine and the abdominal organs, such as the liver and intestines.

The muscles of the back, then, define their functions in relation to the location they occupy in the human body and the other structures with which they are related.

They are muscles that determine body posture, but also regulate the three basic movements of the trunk: flexion, rotation and extension. For the field of occupational medicine they are a study objective, due to the work injuries associated with it.

They contribute to the protection of the thorax and abdomen organs, forming part of the walls that isolate them from the outside. Some of these muscles, usually the smallest, are part of the mobilization mechanism of the upper limbs.

We are not going to describe all the muscles of the back, but yes We will see a panorama of the most relevant, dividing them into three regions, according to its depth. We will talk about the deep, intermediate and superficial muscles.

Muscles of the back of the deep plane

They are the ones that are farthest from the surface and closest to the internal organs, and in close link with the spine. As a general group they extend from the neck to the sacrum. They fulfill a basic and primordial function: control the posture of the whole body.

Let's see some:

  • Spinal: they are along the entire spine, between the spinous processes and the transverse processes of the vertebrae. Scientific studies of recent years have discovered how bad job positions are affecting them. We distinguish two types:
    • The interspinous they join the spinous processes of different vertebrae. They are extenders of the column.
    • The intertransverses they do the same with the transverse process. They serve for lateralization movements.
  • Sacrolumbar: They are the ones that join the pelvis with the spine, reaching some cervical vertebrae. They are able to extend the column and also play a very important role in tilting the trunk sideways.
  • Dorsal Serratos: There are two varieties, the serratus cranial or postero-superior serratus and the serratus caudal or postero-inferior. They are muscles that participate in the breathing dynamics, helping the thorax to breathe out and inhale. They originate in the spine and are inserted in the ribs.

It may interest you: The relationship between the spine and the organs

Muscles of the back of the midplane

Simplifying, We can summarize the function of this muscle group in regulating the movements of the scapula. They are, therefore, in direct link with the bone we know under the name of scapula.

This bone is articulated 'falsely' with the rib cage. It is known as a 'false articulation' because it is not typically constituted, like the other joints, but rather it is a bone surface – the scapula – on muscles – serratos –.

Here we will name:

  • Angular of the scapula: It is the elevator of the scapula. It could also be classified as a muscle of the upper limbs by the objective that it fulfills. It is born in the shoulder blade and reaches the cervical vertebrae.
  • Romboids: When this muscle contracts, it brings the scapula closer to the spine, in an adduction movement. It also communicates to the scapula with the spine in its insertions. It owes its name to the diamond shape it has.

Muscles of the back of the superficial plane

These they are the best known, surely, because they are linked to the exercise of body building and aesthetics. A good development of these muscles of the back generates a characteristic figure in those people who attend the gym regularly.

However, functionally, they have an importance that is far from the aesthetic. The muscles of this plane actively participate in the movements of the shoulder joint.

Discover more: How to do exercises without weights for the back

There are two most relevant:

  • Trapeze: It is one of the largest muscles, with three connecting parts. It has insertions in the occipital bone of the skull, in the cervical vertebrae, in the clavicle, in the dorsal vertebrae and in the scapula. It allows:
    • The shoulder abduction.
    • The approaching the scapula to the spinel.
    • The decrease of the scapula.
  • Dorsal width: begins its journey in the last dorsal vertebrae and in the common aponeurosis mass that form the last three ribs to reach the iliac crest of the pelvis and also insert into the lumbar vertebrae, with an extension that reaches the humerus. It is thin, practically flat and triangular in shape. When the arm acts as a fixed point, prying, it is able to raise the trunk.

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