The Grand Vertebral Column
Annie’s Canyon, Solana Beach, CA
“You are only as young as your spine.
A healthy spine is a healthy life.”
The Grand Vertebral Column
Your human spine is miraculous. It is the communication highway between brain and body. It gives you the duality of mobility and stability. Your spine gives you the ability to express yourself, in large part in how you stack your bones (hold your vertebrae). This may invite greater freedom and health— or harm. Your spine is a paradox of creative expression and steady support, effort and ease.
Let’s dive in. The vertebral column is truly composed of two separate columns. The first column provides stability. It is composed of mostly dense bone (vertebral bodies) with discs that are semi-gelatinous (squishy) in between; the bodies are large (and less movable) at the spine’s base and grow smaller (providing greater movability) as they reach the top. This column is excellent for weight-bearing, stabilizing and reacting to compression forces (think: press together).
In contrast, the second column, adjacent to the first, is a spacious structure built for mobility. It is made mostly of soft tissue like ligaments and cartilage and has just bits of bone (arches). It is a moveable structure that adeptly responds to tension forces (think: stretch apart).
These two structures work together to provide the human body with the full gamut of movement, from being able to stand upright, to moving and doing all the things we do.
Through all the movement it supports, the spine carries an important principle: it inherently seeks to return to a neutral place.
The S Shape
The spine has a natural S shape that further supports both weight-bearing and movement. Your spine has reflective, or mirroring, sympathetic curves that create the S shape. For example, the low back and neck reflect one another. Try placing one hand on your low back (lumbar) and one on your neck (cervical spine) and round forward. Note the (kyphotic) curvature in the neck is mirrored in a stretching of the low back—these sympathetic curves create part of the S shape.
Root to Rise
Try this. Root down through your sitting bones. Opposition-ally, draw your pelvic floor up and in (like a “lock”) and hug in your low belly. Rise taller through your crown. Soften your shoulders so they crawl down your back, and soften your chin slightly under—feel the back of your neck lengthen. Notice the natural S curvature your spine gravitates toward. Your low back tilts back slightly (anteriorly), as does the upper back (opposite of hunchback). Take a few deep breaths and gently observe the mind rather than react to it.
The Spine Also…
Protects nervous system
Distributes weight-bearing forces
Keeps body upright
Attachment point for muscle
Information highway
Connected chain of moving parts, a “kinetic chain”
Overview – Spinal Column, Parts and as a Whole
Curves
Primary (thoracic & sacrum)
Secondary (cervical & lumbar)
Sympathetic (lumbar and cervical often curve together)
Vertebral Columns, Ligaments, Facet Joints
2 columns:
Bodies: Stability—Stability (Sthira): Dense with little soft tissue (discs) – reacts to compression forces
Arches: Mobility— Mobility (Sukha): Spacious, bits of bone w/ ligaments and soft tissue – reacts to tension forces
As the spine is a structure that inherently seeks to return to a neutral place, notice how compressive forces are met with decompressive actions (to return to stability, neutrality).
Ligaments and Structures
ALL: Anterior Longitudinal Ligament, anterior surface of the bodies – stretched back during backbending, loosened during forward folding
PLL: Posterior Longitudinal Ligament, posterior surface of the bodies –stretched during forward folding, loosened during backbending
Backbending forward folding – cause bodies of neighboring vertebrae to pinch together on one side (thus squeezing the disc that lies between them) and draw farther apart on the other
Facet Joints: Connect and protect. Lined in synovial fluid
Spinous processes on back, Transverse processes on side
Backbending forward folding – cause bodies of neighboring vertebrae to pinch together on one side (thus squeezing the disc that lies between them) and draw farther apart on the other—widening the space for the disc, pushing the disc’s soft nucleus toward this open side.
Imbibtion
Imbibtion is the action of vertebral discs passively taking up (“drinking”) fluids from the surrounding tissues. Movement creates and opens space, enabling the absorption of fluids or imbibtion, which keeps the spinal column supple, agile and movable. Without this, the structures of the spine can get “rusty”—they can harden, become immovable and even fuse over time.
The Spinal Segments
Cervical Spine (7 vertebrae, Neck)
Highlights…
Facet joints (not ball and socket joints)
Only encourage movement they are capable of (no rolling neck)
Will reflect the curves below it (backbend/extend lumbar, will often extend cervical)
Kinesiological principle of cervical spine:
Law of side-bending and rotation: side bending and rotation occur to the same side, regardless of the position of the cervical spine at the beginning of movement (when you side bend right, the vertebrae rotate right)
Exception: C1-C2 joint rotates the opposite way when the cervical spine side bends to allow the face to stay forward
7 vertebrae
Curve: Concave, Secondary (develops after birth),
Apex of extension: C4 (point of wear and tear for extension)
Apex of flexion: C5 (point of wear and tear for flexion)
Carrying the head over the body will contribute to overall health.
Note on the Neck
One interesting way to look at the posture of the cervical spine is to think of it as receiving the results of the spinal segments below it. If you slump or stand upright, the neck will be affected; however you choose to hold your lumbar and thoracic spines will create health or havoc for the cervical spine above them. The head and neck posture also signal your mood to the world—poised, assertive, meditative or dejected. The movement of the cervical spine can directly affect the blood supply to the brain.
More on Your Crown Here.
Thoracic Spine (12 Vertebrae, Mid Back)
Highlights…
Attachment point for ribs
Strong protective structure for heart and lungs
Creates posterior armature of the thoracic cage
Curve: Primary (develops en utero), convex (opposite cervical spine)
More stable, less range of movement
12 vertebrae (attached to 2 ribs each)
Kinesiological law of side-bending and rotation:
Occur to the opposite side, except when the movements are begun in flexion, then they occur to the same side. When you rotate thoracic spine to right, you side bend left—this allows us to rotate our ribcage to sky in Trikonosana.
Kinesiology
Flexion: 45 degrees
Extension: 25 degrees
Axial Rotation: 35 degrees
Lateral Flexion: 20 degrees
Lumbar Spine ( 5 Vertebrae, Low Back)
Highlights…
5 massive kidney-shaped vertebrae
Located higher than we might think—L4 is directly behind belly button
Designed to function best as a weight-bearing structure when in neutral – where the vertebral bodies and facet joints can bear weight in a more equal and stable way. Many people have lost awareness of the lumbar curve due partly to sitting hours daily in chairs that favor flexion (flattening of curve/posterior tilt)
Kinesiology
Flexion: 60 degrees
Extension: 35 degrees
Axial Rotation: 5-12 degrees
Lateral Flexion: 35 degrees (limited by ribs, pelvis and soft tissue)
Interesting Lumbar Factoid
Adding up all the degrees of movement in flexion allowed in the entire vertebral column, 50% is created by lumbar spine; of that, 75% is created at L5-S1 joint. Thus, 37.5% of all vertebral flexion occurs at one joint segment. Given the vulnerable position of the L5 vertebra and the amount of flexion allowed, this joint is the site of frequent dysfunction.
Sacral Spine (5 Vertebrae, Sacrum + Tailbone)
5 fused vertebrae in a pyramid shape
Coccyx at distal end, made of 3-5 fused bones (tail bone)
Surfaces join in such a way that the sacrum is at a diagonal angle of ~30 degrees from vertical. Looking at the angle of the sacrum is one way to assess if you are standing with a neutral pelvis. The sacrum should be at an angle in neutral, not vertical. A vertical sacrum indicates a posterior tilt (tucking tailbone) of the pelvis.
Site where vertebral column (sacrum) and pelvic girdle (ilium) intersect
Site of union between upper and lower body
Sacroiliac (SI) are joints of stability. Convex sacrum and concave ilium—to create stability, the joint surfaces are shaped to facilitate the wedging of the sacrum down into the ilia of the pelvis during weight-bearing—this is a self-locking mechanism. Stability is greatest when standing. An unlocking mechanism occurs when sitting partly due to the abdominal muscles being much less active as a support system during sitting and the sacrum not being as firmly wedged down in the pelvis.
Tucking the tailbone tends to unlock the sacrum from the ilium
Posterior wall of pelvis (large part of)
More on Your Low Back and Pelvis Here.
Functional Movement
Functional spinal movements like forward folds and backward bends…
Elongate the spine, encourage elasticity of the spinal column, wake up the cranio-sacral “highway,” and provide a host of other benefits.
