This article was originally published in Positive Health PH Online April Issue 158 may 2009
It might surprise you to know that the word muscle comes from musculus which, in Latin, means ‘little mouse’. And strange as it may be, the word mussel has the same etymology. This is because to the early Romans, the bump that forms and moves when the biceps is flexed was reminiscent of this charming little animal. They surely had a fertile imagination because the shape and colour of the shellfish they used to serve at banquets also reminded them of a little mouse. In other words, if I may say, when you use the words muscle and mussel, literally speaking you are talking about a little mouse.
Words can be manipulated and used in a way that makes them convey something totally different from their original meaning. Politicians and PR people know that only too well, and here the word ‘freedom’ comes to mind. Even anatomists, in spite of their scientific leaning, are not immune to stretching some words to a point where they lose their original meaning. The misuse of words can have, in this context as in others, a conditioning effect on concepts, theories and, ultimately, treatments. Good and sound communication requires that crucial words are properly defined at the start. That’s why I propose to dissect some words commonly used in anatomy and physical therapy.
Let’s start with the word extension. To extend is to stretch out, lengthen, straighten at full length. So an extension implies an increase in length and an extensor is a muscle which extends or straightens a limb or the spine. For example, the triceps brachii, a muscle that runs at the back of your upper arm, extends (straightens) the elbow joint, and the quadriceps, the big muscle at the front of your thigh, extends the knee joint. Here, the word extensor is correct and the muscles aforementioned ‘deserve’ the appellation. But when we turn our attention to the back muscles, confusion reigns. The posterior muscles of the trunk (the ones that drape your back), have been labelled by anatomists as extensor muscles. Unfortunately, if there is one thing they can’t do, under any circumstances, is to extend, that is straighten and lengthen the back. Being situated in the back, they can bend it backward; running on each side of the spine, they can side-bend it; having a diagonal direction, they can twist (rotate) it. They can even perform these three actions at the same time, which, by the way, explains the condition known as scoliosis. And believe me, they are not slackers but rather zealous in carrying these actions out, but again, and I won’t apologize for repeating myself, they never will extend the back. To call the back muscles ‘extensors’ is to misname them.
You might be wondering where on the body are these extensor muscles of the back if they are not in the back. Don’t waste your time looking for them because, although I would hate to disappoint you, I have to tell you the truth which is that when it comes to the spine there is no such thing as an extensor muscle. There are flexor muscles: antero-flexor muscles that bend the spine forward, and postero-flexor muscles that bend the spine backward. The so-called extensor muscles of the spine are impostors; in reality, they are postero-flexor. A true extensor of the spine would have to have one point of attachment at the top of the skull and the other at… the ceiling?! Evolution has not managed that yet. It is one of the reasons why advising people to think of having a balloon on the top of their head in order to grow taller is, at best, useless.
If you think that I am just splitting hairs (or muscle fibres!), think twice. To misname is to mislead. Since extensor muscles of the back do not exist but are instead postero-flexor muscles (bending the back backward) what do you think happens when you work assiduously at strengthening them? Instead of lengthening your spine, you shorten it! You do the exact opposite of what you intended. The path that leads to distortions and pains is often paved with good but misguided intentions. It is especially misguided to try to strengthen the back muscles since they are links in a long chain of muscles running from head to toes (one of the muscular chains discovered by F. Mézières). As such they are very strong and tight, and never miss an opportunity to contract and shorten; it is actually very difficult to prevent them from being recruited in any and every movement we make.
Knowing that the long bundles of muscles that cover the back in a chain-like manner always end up too short, it is inevitable that the curves of the spine have to increase their arches in order to yield to this compression force. The result is a shortened, slouched stature. Now, if one believe that these very muscles are supposed to straighten one’s back it’s normal to think, logically but erroneously, that they are too weak for the job, and to want to strengthen them. It is not a surprise therefore that exercises to do just that abound. Practically speaking, it means that whenever you diligently – and painfully – practise Yoga or Pilates postures such as the Cobra, the Prone Boat, the Rocket Man, the Naughty Child, the Down Dog (the list is not exhaustive), or any other similar ones coming from other sources, you delude yourself if you think that you are going to improve your posture and become straighter and taller. The reverse is true.
Due to space constraint, I cannot further extend this column. But do not despair because in the next one(s) I will dissect some more anatomical terms and you might find out how one can extend one’s spine without extensors.