Anatomy of the Spine.
A basic vertebra is comprised of a bony block and a bony ring. The block is sandwiched between disks. The ring houses the precious spinal cord. The ring consists of 2 pedicles, 2 lamina, 1 spinous process, and 2 transverse processes. Processes are levers that attach to muscles. Each vertebra has 4 facets [joints], 2 superior, 2 inferior attached on the lateral posterior side of the vertebral body. A thoracic vertebra has 4 more facets attaching to the ribs. Facets are the synovial joints of the spine. This means they have a synovial membrane that secretes synovial fluid, and a capsular ligament that holds the synovial fluid. The angle of orientation of the facets changes with each vertebra. The angle influences the direction of movement.
The spine is segmental, consisting of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral [fused], and 4 coccygeal [fused] vertebras. We must consider that each vertebrae has any direction of movement. The image of vertebra floating in all directions is useful. We categorize each vertebra movement as flexion, extension, rotation, and side bending. Some vertebras move less, some more. This is called the relative flexibilities/inflexibilities of the spine.
Lumbar vertebras are massive for weight bearing. The facets have a sagittal orientation allowing little rotation, but a lot of flexion, extension.
Thoracic vertebras are medium size with ribs attached. Ribs are the armor of our vital organs. We have 4 more facets per vertebrae. These are more facets to become hypomobile and restrict spinal movement. The spinous processes are sharply angled down to prevent excessive back-bending.
Cervical vertebras are the smallest, designed for mobility of our head. Facets are angled at 45 degrees from the horizontal.
Spinal ligaments allow efficient passive joint stabilization. They limit and direct vertebral movement. These ligaments have many pain receptors. The anterior longitudinal ligament [ALL] is thin stretching from the occiput to the sacrum. The ALL stretches with backbends. The posterior longitudinal ligament [PLL] is thick, but tapers from the lumbar to the sacrum. The PLL stretches in forward bends. There many more spinal ligaments connecting vertebras to each other in every imaginable direction.
Disks are fluid filled cylinders. Their water content decreases with age. Most disk surgery is performed on people in their 30's to 50's when the water content is enough to make them bulge. Normal spinal curves allow even disk compression. There is 3x more interdiscal pressure in sitting than in standing.
Muscles are divided into 2 types. Deeper, postural muscles sustain posture with lower energy. Surface, phasic, 2 joint muscles are quick and explosive. The muscle contractions can be concentric [shortening], isometric [same muscle length], or eccentric [lengthening] contractions.
Normal weight bearing through the spine is a tripod design. The 2 facets in the back and the disk to the front. The disk / facet weight bearing is [80 / 20] through the lumbar spine and [50 / 50] in the cervical spine.
Ideal Human Posture and Movement
Hatha Yoga can be defined as conscious, skillful movement. Movement can be efficient, graceful, fluid, and functional. Victor van Kooten teaches that we need a clear vision, a well defined mental image of space within and around us to allow energy to flow in the direction of our awareness. This manifests as movement of our human form. With our intention of posture or movement, our energy body, also called inner body or pranamayakosa, can move our physical body, also called outer body or annamayakosa. We need to be aware of kinesthetic [body] sensations. We interpret sensation as the perception of posture and movement. We can interpret intense sensation as injurious pain or therapeutic release of restrictions. We need to let go of our muscular surface body enough to allow the inner body guide our physical body in an efficient, fluid, graceful way. Or we can let the muscles strongly impose movement upon ourselves.
We can set ourselves up to let go into the support of the earth in restful restorative poses. Breath is our vehicle into the inner body. As we inhale, we can allow expansion [space] from our center outward. As we exhale, we can release, let go of our blocks and restrictions.
We can intend our extremities to ground through the earth, as we support and move our centers in the up/down dog continuum. Our vision as quadrupeds keep us concerned with connecting to mother earth, no lofty aspirations.
In standing poses, inversions, or upright sitting, we soar skyward through the crown [or feet] because of our vision of the foundations into earth supporting and our centers expanding and ascending. Lofty visions of lightness in stance and in sitting. Our vision facilitates our nervous system to organize our skeletal and muscular system to move us skillfully. The foundation of rooting is the skill of connecting downwards into the earth. Our relationship with earth is to acknowledge her as our support. We move from our center through our trunk and extremities. As bipeds we need to appreciate the vertical. We need to find neutral in terms of our bony alignment, our joints. We need to ground and lift [or be lifted] along the vertical.
We after all are upright beings.
As we ground [root], we connect and move upon mother earth. The direction of grounding is directly opposite to the direction of movement of our center. For example, as we push down and forward through the ball our hand, our bellies move up back away in down dog. If we root straight down through our feet, we lift [or are lifted] straight up through the crown of our head.
Rajasic rooting pushes the earth away or towards us. Inner spirals of "rocket pose" propels us upward. Tamasic rooting releases our outer body into the earth, in widening mountain pose, as we receive the lift through our centers upward. Victor's image of the cosmic egg works well here. (The image of the "cosmic egg". We attend to space, expanding outward from our center, we release our surface body downward through the corners of our feet through the earth and allow the roots to curve into a center that rises back through the earth into our center of arches, perineum, pelvis, and head creating lightness and length of spine).
As bipeds we are designed to be upright, though connect to the earth, we lift towards the vertical or soar to the heavens. We ground in standing by reacting [ in a rajasic or tamasic quality] to the increased weight [therefore sensation] in one or a few of the 4 corners of each foot / hand. We press or release into that sensation to keep center of gravity [usually belly / heart] within the support extremities. We visualize extending from ones center downward through center of leg / arm through the 4 corners of each foot /hand into the earth. We could visualize roots descending, in a downward direction beyond the physical extremity [tamasic root.] Or we could visualize pushing of mother earth away [rajasic root.]
We ground in sitting through the 4 petals [sit bones, tailbone, pubis] and lower extremities to allow a rising through the muladhara. The direction and degree of rooting through the tailbone and pubis determines the orientation of the pelvis therefore trunk and head.
We ground in quadruped through hands and feet, directing the movement from crown to root and beyond into down dog. Or we could ground through our hands and feet, directing the movement from root through crown and beyond into up dog.
Western science says our nervous system allows us to balance in space, using our righting and equilibrium reactions in this upright world. Closed chain reactions of weight bearing and weight shifting cause a sequence of biomechanical events to start from the ground upwards. Open chain reactions as countermovements, as in protective extension or staggering. Or as Victor says, we can release into the earth and rise along the limitless energy into lightness along Shiva?s lingam. The West has studied the transitions of movement to and from positions of supine, prone, sitting, all fours, and standing, as well as locomotion in each of these positions. We have studied the quality of tone, primitive reflexes, righting and equilibrium reactions in movements such as rolling, come to sit, crawling, rise to standing, cruising, and ambulation.
Hatha Yoga also looks at how easy and comfortable poses can be as we move in and out of them as in surya namaskar. Angela Farmer has said that asanas are pauses in a continuum of this skillful conscious movement.
Developmental therapists evaluate disassociation from primitive or habitual movement, by influencing tone, primitive reflexes and facilitating equilibrium reactions. They can treat people from this perspective very effectively.
The goal in the West is purposeful, functional posture and movement, stable yet mobile and mobile yet stable, holding midranges to moving towards extremes of range.
Yogas citta vritti nirodhah.
Hatha Yoga is to quiet the mind, to prepare the yogi or yogini with skills of concentration to enter dharana, dhyana, and samadhi. Hatha Yoga prepares one to handle the rigors of sitting meditation. The health benefits are secondary. But the West sees Yoga as exotic exercise, as prescription for healing faulty posture and movement, as stress relief.
Pathological Posture and Movement of the Spine
In Western Culture, we are subjected to the ravishes of chairs, shoes, computers, soft sofas, and cars. We rely too much on our visual orientation. We are "in our heads" much of the time. We are intellectual and emotional but not very kinesthetic. The mechanical stresses of too much sitting tightens our hips, dulls our spine, tenses our neck and shoulders muscles. Cultures that don't use chairs, but rather sit on the floor, as we did as infants and toddlers, maintain normal ranges of motion in their hips. We sit too much in our culture with all the time we spend in cars, computer workstations, and easy chairs. Our spines have relative inflexibilities. We typically have a tight thoracic area with relatively hypermobile cervical and lumbar spines. Cultures, whose people wear sandals or go barefoot, have much less incidence of foot pathologies as those who wear shoes. Unfortunately we tend to be unskillful in rooting during stance and sitting. Just watch people stand with dull spines in banks or grocery store lines. Watch the collapsed hips in lordosis or obliquity, locked knees, flat feet.
Dull sitting causes prolonged spinal flexion and posterior pelvic tilts. Most chairs do not support the pelvis towards neutral or the lumbar spine out of flexion. Therefore uneven compressions in weight bearing lumbar disks pushes the fluid of the disk posteriorly. The front of the vertebral body pinches more, so the fluid migrate backwards, pressing against the posterior lateral wall of the disk, where there is the lack of PLL. There is [3x] increased interdiscal pressure in these lumbar disks by slump sitting in chairs [compared to standing]. Eventually lateral posterior disk wall degenerates under this pressure causing herniation. The bulge lowers the height of the disk and decreased disk height lessens space between adjoining vertebrae. This abnormal compression or pressure on the facets causes bone spurs [osteophytes]. These bone spurs then can impinge upon the nerve root causing more pain.
A common diagnosis today is sciatica [inflammation of the sciatic nerve]. One typical way the sciatic nerve is inflamed is by nerve root impingement. A lumbar disk bulges out into the space where the sciatic nerve roots exit out through the foramen between adjoining vertebras. This bulge presses against the nerve root inflaming it, causing paresthesia. Paraesthesia is numbing and tingling down the back of the leg.
Muscles are irritated as well and reflexively respond with tension and spasm. Inflammation of soft tissue is very painful. Muscles, tendons, ligaments, and fascia are irritated by the bulging disks. The chemical process of inflammation produces substances like free radicals that irritate surrounding tissue. Also lactic acid is a by-product of the chemical reaction of muscle contractions. These are all irritants to soft tissue. Muscles respond to the irritants by reflexively spasming as a guarding to attempt to immobilize the back. When one "throws their back out" when already tensed, vulnerable back muscle strain or tear upon loading. Simple activities like standing up out of a chair, raking, shoveling snow can be life altering events.
Yoga for Discogenic Low Back Pain
Robin McKenzie is a famous New Zealand physiotherapist who designed an extension protocol for discogenic back pain. He would suggest no sitting, no seated forward bends, no standing forward bends for someone with acute sciatica from herniated lumbar disks. He felt that spinal flexion was the cause of the herniation and would perpetuate the symptoms. If the back was not too acute, he would immediately start a regiment of spinal extensions [backbends]. His "press ups" were similar to cobras, his "press backs" were similar to a preparation for a drop back. His protocol would be for 3 sets of 10 press ups every waking hour once the patient could build up it this level. He sees backbends as "rest time" for a disk. Extension would not push the disk fluid to the weakened or cracked posterior disk wall as spinal flexion would. One would also avoid stretching the back of one's leg that would stretch a highly inflamed sciatic nerve causing more sciatica.
If the soft tissue in one's back is acute, inflamed, and in spasm, resting in neutral is first. Supine with calves on a chair seat is a supportive restful position. But once the back musculature is not so reactive to movement, extension should start as soon as possible. Yoga adds to McKenzie's ideas with the lengthening, lightness, space within the spine. Yogis know that the energy within the trunk, rising along the vertical is very important. Length and space in the lumbar spine in cobra and up dog are necessary as so not to compress the lumbar facets or S/I joints. Be careful so as not to stretch an inflamed sciatic nerve if stretching [padangustasana I] causes sciatica.
Typically in low back pain, there is soft tissue inflammation. The muscles are tensed, spasming as a result of the nerve root inflammation. Muscles respond with spasming to immobilize the lower spine guarding the back from inflaming more. So rest has its place. Supine with calves on chair seat is a time-tested favorite. Improving circulation with heat, cold, massage helps process the irritants out the soft tissue. Very gentle stretching to start the person moving. Knees to chest, legs up wall, jathara parivartanasana [flexed knees] are a start towards movement. Many protocols stop here. But these are only the beginning, done during the acute phase.
The primary work of spinal extension [backbends] are an absolutely necessary. Supine Bolster Work is a personal favorite of mine. It is passive, releasing, calming, energizing, massaging all at the same time. Prone Mechanzie activities like press ups and press backs work well. Yoga adds bhujangasana [cobra], urdhva mukha savanasana [up dog], setu bandha sarvangasana [bridge], ustrasana [camel], and urdhva dhanurasana [wheel].
Upright vertical spines decompress the disks, normalize the curves, regaining the tripod support of weight bearing. Standing Poses are great forms to learn the liveliness of the spine. The foundation to the lower extremities, centering of the belly/ pelvis, and directing the energy through the spine and out the crown are valuable skills to learn. Eventually one can move towards drop backs from tadasana with long, energetic spines.
Sitting continues to be a provocation. Even though there is 3x the interdiscal pressure in sitting, it can be tolerated. It is better tolerated with upper sacral and lower lumbar support, recline, and good foundation for sit bones, thigh bones, and feet.