The Importance of Abdominal Muscles in Relation to the Spine

Anterolateral Abdominal Muscles Importance
It’s very important to note that the movements of the vertebral column are not produced exclusively by the back muscles. In fact,they are also assisted by gravity and the action of the anterolateral abdominal muscles, which include the following five muscles:

 

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Source: Clinically Oriented Anatomy, 4th Ed Keith L. Moore & Arthur F. Dalley

 

1.Transverse Abdominal
2.Rectus Abdominis
3.Internal Oblique
4.External Oblique
5.Pyramidalis

If any of the above muscles are compromised in any form, this may also affect a particular movement of the spine this compromised muscle usually helps to produce or is responsible for producing, to an extent.

The Role of The Anterolateral Muscles in Relation to The Vertebral Column
Transverse Abdominal
It’s believed, that the transverse abdominal muscle probably has no appreciable impact on the vertebral column.
 Rectus Abdominis
Apart from compressing and supporting abdominal viscera, it also flexes the trunk(lumbar Vertebral). Overall, the rectus abdominis is believed to be a powerful flexor at the thoracic region and in particular the lumbar region of the vertebral column.

External Obliques
Not only do the external obliques compress and support abdominal viscera, they also flex and rotate the trunk. Overall, the internal and external obliques assist in movements of the trunk, especially lateral flexion and rotation of the lumbar and lower thoracic vertebral column.

Pyramidalis
The pyramidalis is believed to play an insignificant role in about eighty percent of individuals. It’s sole role is to act as antagonists of diaphragm to produce expiration.

[P.S. In anatomy, an antagonist is a muscle whose action opposes or counteracts that of another specified muscle.]

The anterolateral abdominal muscles in general, play a vital role in movements of the pelvis when standing, and help to maintain posture. During old age however, anterolateral abdominal muscles’ looseness or lack of firmness allegedly contributes to abdominal protuberance(enlargement).

Causes of Abdominal Enlargement

Tumors and organ enlargement will also cause the abdomen to become enlarged. As the abdomen increases in size, the anterolateral abdominal muscles have the tendency to shrink (atrophy). It’s believed that the five common causes of abdominal protrusion are the build up of fat, feces, fetus, flatus, and fluid.

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Going back to some of my past lecture notes, anterolateral muscles that are underdeveloped, atrophied (waste away or shrink) do not have enough tonus (normal tension of a muscle at rest) to resist the increased weight placed on them as a result of abdominal enlargement. Consequently, the anterior pelvis will tilt anteriorly at the hip joint when standing. This excessive convex curvature of the lumbar region may lead to back pain.

General Movement of The Vertebral Column
The average healthy individual should be able to perform these general movements below:

 

Imagevertebral movtmnt (127)

Source: Clinically Oriented Anatomy, 4th Ed. Keith L. Moore, Arthur F. Dalley

Of course, some people are more flexible than others, due to factors such as age, gender, genotype, etc. Although these factors may be good predictors, there are always exceptions. In fact, some people, such as acrobats, gymnast, etc, who started training during early childhood, are usually able to produce some rather extraordinary movements of the vertebral column.

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Photograph: By I.W. McFarlane

The bottom line is however, if an individual is unable to, or is experiencing pain when attempting to perform any of the usual movements of the vertebral column, this should be a matter of great concern! In fact, they should definitely consult their health provider.

Source: Dalley F. Arthur; Moore L. Keith, Clinically Oriented Anatomy; 4th ed

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