In a class of yogasanas, you will often hear the teacher calling the instruction, 'Keep the spine erect.' Let us see the implications of this instruction. In kundalini yoga, it has a significance of its own as far as the nadis and chakras are concerned. But in this article we shall consider only from the anatomical point of view.
The foetus, lying all curled up in the mother's womb is safe and secure, floating blissfully in the amniotic fluid, insulated from the shocks and sounds of the outside world. All its joints are flexed. If it tries to raise its head at the time of birth, it creates troubles both for itself and for its mother. At delivery, it usually presents that portion of the head which lies between the locations of the sahasrara and the bindu to the world. If it fully raises its head in arrogance, making a face presentation, a normal delivery is impossible. Thus, the spine is flexed (bent forward) at the beginning. Later, when the infant turns on its tummy, and starts to raise its head, it develops the first backward curve of the spine, in the cervical (neck) region. Still later, when the young child first stands on its own feet in the erect position, it develops another backward curve in the lumbar (lower) region.
The major evolutionary advancement of man over the rest of the animal world began with his assumption of the erect posture. The ape, whose erect position is not nearly as well developed, is supposed to be our nearest ancestor. When man ceased using the fore limbs for locomotion, i.e. for walking or running, these became upper limbs or arms. Only after assuming the standing posture did he begin to make use of them in many new ways. He started lifting his food with the hands and taking it to the mouth. As a consequence he no longer needed to take his mouth near his prey or food, to pick his morsel. Nor did his jaw have to tear so forcibly. Hence the form of his teeth and jaw changed. He could now produce more delicate and diverse types of sound with the mouth and thus language began to evolve, crossing a second major evolutionary barrier (and eventually leading to today's linguistic diversity - the Tower of Babble). But this is beside the point.
What matters to us here is the backward lumbar curvature of the spine, which man developed after standing erect. The lumbar spine has to bear the weight of the upper half of the body in the erect position. Due to this and also to strides of the legs in erect walking, the spine developed this backward curvature which predisposes man alone amongst all the animals to a new range of evolutionary spinal diseases including low back pain, slipped disc, sciatica, scoliosis and spondylitis. In addition, various disturbances of digestion, menstruation and reproduction arise due to congestion and irritation of emerging spinal nerves in the lumbar region. Another disadvantage of the erect posture is the increased likelihood of developing piles (haemorrhoids) and varicose veins, because the column of venous blood from the legs and rectum has to travel so much further upwards against gravity to reach the heart.
The spine is like the trunk of a tree, supporting the entire body structure. Atop this trunk sits the bony, enclosed cranium or box of the skull, containing the most important of all human organs - the brain- which not only controls the human body, but gives a real purpose to its existence.
The top-most vertebra is called the atlas, because it supports the round head like the Greek mythical figure Atlas, who supported the earth upon his shoulders. The second vertebra is the peg-like axis, so named because the atlas and skull rotate upon it. Thus, the head moves both independently of the movement of the neck, and with the neck as well. Of the 33 vertebrae of the column, these are the only two which are named. All the others bear only numbers.
In the thoracic region, the spine supports the expansive rib cage, which is composed of bones (ribs), muscles and cartilage. The rib cage surrounds the lungs and the heart, which are next in importance to the brain. The lungs purify the blood, while the heart circulates it to the entire body, supplying the cells and tissues with all their nutrient requirements, and taking away their waste products.
In the lumbar or abdominal region, the spinal column serves as an anchor for the muscles which hold the gastro-intestinal organs in place: stomach and intestines, liver, spleen and pancreas and also the kidneys and urinary system. These are held suspended as if in a cloth handbag with the spine forming the handle.
At the lower (sacral) end of the spine is the pelvis which is like a bony basket or cavity cradling the excretory and reproductive organs. Here the fertilized human egg is nurtured in the mother's womb, like a bird's egg in its nest.
Like the main branches of this tree, the upper and the lower limbs shoot out from this central trunk, with the nearer joints (the shoulder and the hip) having a full range of movements in all the three planes like a ball and socket, while the distal joints (the elbow and the knee) can move in only one plane, like a door on a hinge.
Thus, we find that the spine is not absolutely erect in the true sense of the word, but has four distinct curvatures. The cervical curvature in the neck has seven vertebrae, the dorsal in the chest has twelve and the lumbar in the lower back has five. Like a stack of coins these bear the progressively increasing weight of the column above. Thus each vertebra is slightly larger than the one above as we descend from the neck to the buttocks. The atlas is only ¼ as large or heavy as the last lumbar vertebra. In Sirshasana (headstand posture) one should bear the weight of the entire body on the triangle formed by the head and the two elbows. If too much weight falls onto the cervical vertebrae alone, they will suffer damage as they are meant to carry the weight of the head only and not that of the whole body.
The sacral vertebrae (five in number) are fused to form a single bone at the back of the pelvis. These are smaller as they have no weight-bearing function and take no part in the movements of the spine described above.
The coccyx is the vestige of the tail. The tail is used by lower animals for warding off troubling insects, for holding onto a branch and for balance while jumping. A man can perform these functions with his upper limbs. It is also used for expressing emotions like anger and fright. Human beings have evolved better ways of expressing emotions and man has lost his tail during evolution.
The human spine is not a single bone, nor is it like bamboo. It is like a string of beads, but instead of the string holding the beads together as in a japa mala, it is the beads (the vertebrae) that protect the string (the spinal cord) inside. The spine is made this way because it has to perform so many movements. It bends forwards and backwards and sideways, and also twists up on itself- hence the string of beads. There is a degenerative condition called bamboo spine (ankylosing spondylitis) where the spine really becomes like a bamboo (and looks like one on X-ray). Just imagine the miseries of that person - stiff like a bamboo.
Between two beads there is a resilient disc or pad to absorb shocks while walking, running, jumping or even while standing and sitting. Thus, wear and tear on the bones is lessened and the brain and internal organs are cushioned. The delicate string of the spinal cord runs through the central vertebral canal, and numerous nerve branches emerge from it and pass through the gaps between the vertebrae.
Now, let us proceed to see what afflictions the spine can have, and the role of yoga in prevention and cure of some of them.
At the outset, it should be stated that where the bone tissue of the vertebrae itself is seriously diseased or has been destroyed by a disease like tuberculosis, cancer or a serious injury, the lost bony structures cannot be restored by yoga. Yoga helps maintain and restore the auxiliary structures like the ligaments which hold the vertebrae together, the joints and the shock-absorbers in between, and the para-vertebral muscles on either side of the vertebrae. Yoga also helps in aligning the curvatures of the spine, maintaining the full range of spinal movements and flexibility and relieving pressure on the nerves emerging between two vertebrae. All the yogasanas have some action on the spine, in addition to their other individual actions and applications. The backward bending, forward bending, and sideward bending asanas have obvious actions on the spine. Even the balancing asanas and sitting postures help to maintain the para-vertebral musculature.
Matsyendrasana and its variation, ardha matsyendrasana, demand special mention. These are the only two asanas which give a complete rotatory movement to the entire vertebral column; the locked position of the leg and the arm acts as a fulcrum for the twist.
The natural curvature of the spine in the neck region is backwards, but most of our time is spent working with our heads bent forwards. Hence we get degenerative diseases like cervical spondylolysis. Perhaps we should follow the example of the great artist, Michelangelo, who preferred to lie on his back to paint his murals on the ceiling. These spinal diseases are prevented and also cured by giving extension to the neck. The orthopaedic surgeons (bone specialists) manage it by supplying a supporting collar, or by confining the patient to bed and applying traction on the neck, like a man being hanged. Yoga effectively arrests and alleviates the condition by simple postures including pawanmuktasana, bhujangasana, vajrasana, shashankasana, dwikonasana, ardha matsyendrasana and allied backward bending asanas.
The second malady in this region which is relieved by yoga is tension headache. Due to mental and postural tensions, the muscles at the back of the head and neck become tightened and spasmed (they can be felt as hard tender cords and knots). This causes an ache at the back of the head. Asanas like pawanmuktasana series involving free movements of the neck release the tension load in the neck muscles, while yoga nidra and shavasana reduce the levels of psychic and mental tensions. This double-pronged attack on the disease using somatopsychic and psychosomatic techniques proves most effective. Tensions in the mind and spasms in the muscle disappear reciprocally. Just as mental tensions lead to muscle spasm, so also by lessening the spasms in the muscles one can relieve the mind of some of its tensions. The work of modern psychologists Wilhelm Reich, Ida Rolf and Alexander Lowen has reiterated that our muscular armour mirrors our mental anguish and vice versa.
In the thoracic (chest) region, the spine is bent forward. If it is excessively bent, congestion of the thoracic nerves and crowding of the rib cage result. This reduces the space in which the lungs can expand and respiratory efficiency diminishes. Stooped shoulders and hunched back occur in asthma and chronic bronchitis. These deformities can be removed by practising dhanurasana, chakrasana, bhujangasana, matsyasana and the like. At the same time the efficiency of the respiratory system increases and the symptoms of respiratory disease diminish. A man who is confident of his abilities, walks and talks confidently. He holds his spine erect and shoulders pulled back. This posture in turn helps to instil further confidence.
The most troublesome area of the spine is the lumbar (lower back) region. Its problems are manifold. The para-vertebral muscles become stiff and painful with build-up of emotional, sexual and menstrual tensions. They sprain by uncoordinated actions while lifting, bending or driving. Spinal ligaments are torn by hard pulls or blows received during sports, etc. The muscles are imbalanced if the body weight is not equally divided between both legs due to some disease in the lower limbs. In slipped disc the cartilaginous ring of one of the shock-absorbing spinal discs ruptures due to wear and tear, and its nucleus pulposus may pop out and press on a nerve-root leading to sciatic pain in one or both legs, The most common cause of low back pain is due to bad posture. We are not able to stand or sit properly due to weakened muscles, lack of exercise and sedentary life.
It also suffers from causes in front, when the abdomen becomes obese, flabby and distended. The lumbar spine acts like the handle of a bag holding the contents of the abdomen. In obesity, the contents of the bag become heavy due to deposition of extra fat in the mesentery of the intestines. Mesentery is the supporting structure that straps the intestines to the spine. In an obese person, mesentery is one of the major depots of extra fat. The abdominal muscles support the contents in the bag from in front. If they are weak and flabby, the intestines fall forward, causing a pull on the vertebrae behind. This also leads to backache. Excess fat deposition in the abdominal wall also causes a pull on the lumbar vertebrae. In women, if the uterus is not properly placed (retroversion), or if it has adhesions, low back pain may result. Pelvic infections are another cause.
Major organic diseases of the bones of the vertebral column such as tuberculosis, cancer and osteomyelitis are rare causes of spinal pain. There are many other common causes of pain in the spine which can definitely be successfully managed and corrected by yoga techniques.
The forward, backward and sideward bending asanas mobilize the inter-vertebral joints, develop the supporting musculature of the spine, strengthen the ligaments and massage the nerves and blood vessels. These are essential if proper spinal health is to be maintained, especially in middle and later life. Because this development and maintenance occurs equally on each side, the possibility of unequal tensions on the spine is reduced. In the so-called 'slipped disc syndrome', including sciatica, the backward bending asanas of the lower spine, e.g. shalabhasana, ushtrasana, dhanurasana, and bhujangasana, are akin to the extension exercises given by the physiotherapist. Shavasana relaxes the entire musculature. Tadasana stretches the spinal ligaments, relieves pressure on the inter-vertebral discs and lessens wear and tear. Similarly, the inverted asanas (Sirshasana, sarvangasana, Vipareet karani mudra) change the pressure points, where the body weight is brought to bear on the lumbar vertebrae. This reduces strain on the lower back. Bhastrika pranayama, uddiyana bandha, agnisar and nauli develop the abdominal, musculature, remove obesity and resulting spinal strain.
In fact, over 80% (4 in 5) of all cases of backache are due to causes which can be prevented or alleviated by the correct application of simple yogic methods.