The Axis: The Back II - Muscles.

Now that we know that the spine is built by one vertebra above the other with it's healthy curves and properties, is time to talk about how the spine integrates with the other parts of the body. The measure in which we realize this and make it ours, we will transform our yoga practice (in case we have one) into a more mature practice, and most importantly our daily life.

The spine is surrounded by many muscles and ligaments on different layers. These muscles relate the spine to the pelvis, the legs, the head, the shoulders, the arms, the chest, the groins, and the abdomen (as you can see, with the whole body). Their proper use will lead to a healthy, fluid and beautiful posture in life (I am not refering to an asana) and will spare you from future suffering. The knowledge of these muscles will take you to flex or extend your pelvis, to arch or bend your spine, to turn your shoulders, yo widen the chest, or to ground your sitting bones and grow up like a tree rooting in the earth.

In between the vertebral bodies, it's possible to find some sort of cushions which pad the contact between them called intervertebral disks. When weight and pressure are too much or the discs, the semisolid content of them spills out pressing the spinal nerves and causing an awful lot of pain.

The most vulnerable parts of the spine are only protected by muscles. The cervical vertebrae which "only" carry around 5 kg are surrounded by fewer and thinner muscles than the lumbar which has the whole weight of the upper body, this is the reason why inverted postures, like head balance and shoulder balance, in which the weight of the body is very much on the head and neck should be approached with lots of care so as not to damage the cervical region permanently. The lumbar portion of the spine is protected at the front by a group of muscles called the "abdominal muscles", which are mainly three: the Rectus abdomini, the Transversus abdomini, and Obliques. The back of the lumbar is protected by the Latissimus dorsi and part of the muscular system called the "Erector spinae" which is in charge of keeping the spine upright. (See picture A)

Picture A. The many muscles of the back.

There are very many muscles that work in the spine, but the ones we will focus on for the time being are the abdominal muscles, the Latissimus dorsi, the erector muscles, and the Iliopsoas.

The Iliopsoas is a key postural muscle, it a flexor of the pelvis, that means it tilts your pelvis into the forwardbend position. It is composed by two smaller muscles (Iliacus and Psoas major). The Iliacus starts on the pelvic crest and ends on the outer edge of the femur head (lesser trochanter). The Psoas major starts at the transverse processes, bodies and disks of the lumbar vertebrae and the 12th toracic vertebra, and finishes at the same place of the Iliacus at the outer edge of the femur. (See picture B)

Picture B. Iliopsoas. Note how the insertion of both muscles is on the outer edge of the femur head (EVEN IF IT APPEARS TO BE ON THE INNER SIDE, THE MUSCLES GO AROUND THE BONE!)

Strengthening the Iliopsoas could tilt the pelvis into an exaggerated flexion which could cause the disks (rememer the cushions) to spill, while stretching it will take the pelvis into its "backbend paddling".
One way of strengthening the Iliopsoas muscle is through "ab crunches". Paradoxically, excercising the abdominal muscles is meant to stabilize the lower back, however, according to Profesor David MacAmmond of Calgary, Canada , specialized in therapeutic yoga and kineseology, very little people who practice abdominal crunches have a healthy back due to the overstrengthening of the Iliopsoas.
A good way of just excercising the abs without getting the Iliopsoas engaged is the following.

1. Lie on your back and bend your knees if needed.
2. put your hands beneath the head.
3. Try to lift your nose around 1 cm and feel your abdominals getting worked.
4. Repeat 5 times.
5. Now try to mimic that abdominal contraction without lifting your head.
6. Repeat 10 times.

Through this excercise, nobody will ever develop a six pack, but that has never been the point of working the abdominal muscles. You want to protect your back, not to be a Greek sculpture with lower back pain! :)

Another important muscle is the Latissiums dorsi (See picture C), which involves the movements of the arms with the spine. It also connects the sacrum with the back.

Picture C. Latissimus dorsi

The Latissimus dorsi is the largest muscle of the whole body. It starts at the sacrum, the spines of the thoracic, lumbar vertebrae, lower 3-4 ribs, and iliac crest, and inserts into the inner edge of the humerus (the upper bone of the arm) as shown in the picture.

The fibers of the Latissimus dorsi are transverse. Transverse muscles are not meant for making small efforts for a long time, but rather for making a big short effort, therefore, the Latissimus dorsi must not engage in carrying the spine. The best way of not getting it involved is by widening it and giving space to the other deeper muscles (Erector spinae) to act. Dona Holleman proposes quite an innovative way to widen the Latissimus dorsi while sitting: she says that through the rooting (not pressing) of the outer wrist on the thighs, the Latissimus dorsi moves out of the way of the erectors of the spine. (This outer wrist point is known in Chinese medicine as the gate of heaven)

The erector muscles of the spine are many and are the ones responsible for lifting the spine and keeping it up throughout your life (See picture D).

Picture D. Erector spinae muscles.

There is no particular way to activate this muscles since it is very hard to feel them. What I know through practice is that there needs to be widening of the Latissimus dorsi and rooting of the part which is in contact with the ground so the ground pushes your body up (3rd Law of Newton). Dona Holleman also states that one of the mantras of posture is to keep the sacrum away from the lumbar region. This is done through the rooting of the grounding part on the one hand, and the elongation of the other end on the other.

One good way of excercising these muscles is to stand up straight keeping the sacrum away from the lumbar, feet at hips distance, shoulders above the hips and ears above the shoulders (Tadasana or mountain's pose), respecting all the natural curves of the spine and placing a 6-8 kg sandbag or book on top of the head. Try to lift the sandbag with your head keeping your ears away of the shoulders as much as possible while rooting the feet without pressing or blocking the knees. Feel the widening of the Latissimus dorsi and the elongation of the Erector spinae. This is the same action that takes place in most of the asanas, particularly on the standing ones. Once you have clear mastering of this concept you will be able to stand on your head which involves among a few other things, rooting the head on the floor, and elongating the feet upwards. Doing this will allow you to stay on your head for more than 10 minutes (otherwise you would be using the Latissimus dorsi!) [Do not go into head balance until you have a steady practice, and most certainly don't do it without supervision]

Note how upright are these Gujarati women carrying water on their heads.

Gujarati women carrying water on their heads.

I hope I have given some clear and useful information. Keep tuned for more of other stuff :)

The Axis: The Back I.

This is the first part of the hopefully many of "The Axis". The main intention of this whole serie is to show the anatomy of the body in relationship with the right alignment, as well as eventually some asanas explained in detail. The intention of this first issue is to describe the spine and its morphology.

Picture 1. Right Lateral View of the Spine, taken of the Atlas of the Bones by Marieb.

On picture 1 it is possible to see a right view of the spine, if you have trouble with laterality, the smooth side (he one to your right) is the front face, and the rough part with the spinous processes is the back face. Yes, that is your spine :) Isn't is beautiful? At the top, your spine is articulated with your skull through the so called cervical vertebrae, meanwhile, at the bottom, the sacrum (5 fused vertebrae) articulates with the pelvis.

Due to its relationship with gravity, the  mature, healthy spine adopts two kinds of curvatures. A primary curve is always convex and is called like that because the whole human spine is curved like a "C" in newborn. Secondary curves are concave and are a result of being a Homo erectus.When babies start to crawl and raise their heads to look at things, they start developing the cervical curve. At this point, crawling babies start strengthening their lower backs through adopting a "cobra-like" pose which we will call from now on "baby backbends" (Picture 2). Cute toddlers just stretch theirselves to look up, and while doing so, their lower back acquires the sufficient strength to be able to sit down in an upright position, thus generating a secondary lumbar curve. I just think it's lovely how wise is nature, I heard once, although I am not sure, that if babies are not taught to sit down or to stand up, they actually have the whole instructions to do it by themselves in due time when their backs are strong enough!!! What do you think?
Wrapping it all up, the human spine has two primary curves: the toracic spine, and the sacrum; and two secondary curves, the cervical and lumbar spine.

Picture 2. Baby backbend, taken from http://wyoga.com/wordpress/wp-content/uploads/2011/04/1281127__baby_boy__3.jpg

Picture 3. Posterior view of the spine.

As you can see in both, picture 1 and 3, the vertebrae of the different regions have different shapes, the lumbar vertebrae are wider and thicker than those at the cervical region. This is due to the amount of weight they carry and to their relationships to other bodily structures. Let's see more pictures about it.

Picture 4. The cervical Spine

On picture 4. we can see the shapes of the cervical vertebrae, there are 7 of them. They have no vertebral body, but they are wide, they only support the head and neck. The first and second cervical vertebrae (C1 and C2) are called Atlas and Axis respectively (see picture 5).

Picture 5. Atlas and Axis (C1 and C2)

 Atlas (like the mythological greek that carried the world in Hercules's times)  articulates with the skull. Such a joint permits you to move your head as if you were saying yes (flexion-extension movement). Axis, is articulated to atlas through an extension called "Odontoid (Tooth shaped)  process" (see picture 5). This odonto-atalantic joint makes possible for your head to rotate left and right like when saying no.  if you put your hands behind your neck, and walk your fingers downwards in between the superior edge of the shoulder blades, you will feel a prominent bone, this one is the spinous process of the seventh cervical vertebra (see picture 6). The cervical spine is a concave curve and is not protected by any bone structure, therefore, the muscles in the neck are used to protect it from fracture and tough movements.

Picture 6. Vertebra Prominens or C7

Taking good care of the neck is something everyone should pay attention to. The mean weight of the head lies around 4.5 or 5 kg, that is, somewhere around 8% of your total body weight!!!
 I once heard a chiropractor saying that around 90% of the people who visit him have a condition called rectified neck! As a ball park estimation, I would take it that over half of the world population have rectified necks. A neck goes rectified when the cervical curve begins to disappear. The reason I talk about this is because rectified necks can carry less weight than a normally concave neck!! The loss of this concavity is related to the western posture of sitting down to read, work, and pay attention. also when you read in bead, your neck goes straightened. Neck care goes beyond yoga, seldomly do we realize that we are either overstretching or overextending it!
Asanas like head and shoulder balance where the neck is used powerfully must always be approached carefully. Early practitioners must not attempt to do the full poses before their bodies are ready, even if the rest of the class is upside-down.

The toracic vertebrae are just below the cervical forming a convex curve. There are 12 of them and they are articulated to the ribs, thus forming the rear wall of the toracic cavity. The toracic back is stabilized by the ribcage, this means movility around this area tends to be more limited. Toracic vertebrae have a body and a  formal spinous and transverse processes as can be seen in picture 7.  I will describe all about the function of these processes in the second part of this section where I will talk about the muscles of the back.

Picture 7. Toracic Spine

Kyphosis is the condition in which the toracic convex curve is overdone. People with xyphosis are also caled hunchbacks. Fortunately, most of the people who develop a hunch later in their lives can be alerted of this way before it is too late. Early simptoms include closed and  tight chest muscles, shoulders tight and fallen towards the front, and the shifting the neck forward among others (see picture 8). Working on strenghtening the upper and lower backs, loosening and bringing back the shoulders as in savasana, rooting the feet on the ground, and pulling the ears away from your shoulders can help prevent kyphosis.

Picture 8. Kyphotic spine.

 The last section is called the lumbar region. Lumbar vertebrae have very big bodies as they carry the whole weight of the body in them (no wonder why usually they go herniated). There are 5 lumbar vertebrae, and they articulate with the sacrum which is a group of fused vertebrae (See picture 9). The possition of the lumbar must be mildly concave.

Picture 9. Lumbar Spine

Too much of a concave curve is called Lordosis and can take the intervertebral disks to herniate among many other things. (See piecture 10)

Picture 10. Lordotic spine.

It is the lumbar spine the weakest link in the column for the modern, erect-walking human being. I often find it surprising that in this technological era where new advances and discoveries happen almost everyday, people suffer of lower back problems more than ever. The cause? Well, it is difficult to say it is this or that. Each case is very particular, however today's society is more stressed and sedentary. When we are not sitting down incorrectly at work, we are walking incorrectly or driving somewhere while sitting incorrectly. If you look attentively at your friends sitting down in a chair or couch at a reunion. you will discover that most of them are sitting down collapsed on the lumbar! (This is what many people call "sitting down with the kidneys") When you sit this way, both your toracic and lumbar spines are flexed due to a) a posterior tilt (extension of the pelvis) which moves your lumbar into a convex curve, and b) a forward flexion of the upper back in order "to reach the computer".
The position of your lumbar depends mainly on the position of your pelvis.
Check picture 11, see the different pelvis positions. An extended pelvis (Posterior tilt) produces the collapsation of the lower back, while a hyperflexion caues lordosis (Anterior tilt). The position of the sacrum can hint you on how you are holding your lumbar. Check how the sacrum looks on picture 12, the name sacrum was given because since it is the last bone to decompose, therefore it was considered holly.

Picture 11. Different pelvic positions.

Picture 12. Sacrum

 If you think of the pelvis as a bucket of water, an anterior tilt will spill the water in front of you, while a posterior tilt will spill the water behind you. In a neutral position, the pelvis must not be tilted, however, hinging the pelvis on top of the femur joints is very important in certain asanas. In a forward bend, in order no to compress the intervertebral disks too much, an anterior tilt, or flexion will help you keep your back straight for most of the time, thus protecting the intervertebral disks. A posterior tilt, or "backbend paddling" of the pelvis will be of big aid during backbends and arches helping you stretch the back, creating space between the vertebras, elongating the spine, and avoiding the collapsation of the sacrum into the lumbar.
Try practicing lying on the floor the different possitions of the pelvis as shown in the following picture.

Picture 13. Checking the positions of the pelvis.

I think this is enough anatomy for the day. Next time we will talk about the muscles of the back, the bandhas and standing in Tadasana. Hope you enjoyed it and that it made you direct your attention to how you are holding your back.
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