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Yoga Anatomy

Anatomy of the Spine: What You Need to Know About Your Spinal Curves

How to maintain an optimal (natural!) spinal curve to breathe better, stand taller, and sit longer—on and off your meditation cushion.

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High school gym class is a vague memory. I do remember my classmates and I often being asked to stand close to a wall, turn around, and then try to flatten our lower backs against it. We all stood around the gym, dutifully pushing our lower backs against the hard surface, while our teacher counted to 20 and then repeated. We were never told the benefits, but the subtext was that this exercise helped our backs.

The spine is not a straight line though. I learned this many years later when I studied anatomy in depth. This is true especially when you stand, because the vertebral column bears weight more efficiently and more healthily when you allow it to maintain its normal curves. Consider the spine’s shape, relative to the back of the torso: The cervical spine (neck) curves in, the thoracic spine (mid- and upper-back) rounds out, and the lumbar spine (lower back) curves in again. The base of the spine, the sacrum, is a series of fixed bony segments that also curve in.

See also What You Need to Know About Your Thoracic Spine

We need to let go of the belief that flattening the lower back in a gravity-loaded position protects the spine. In fact, it does the opposite. When you flatten your back, or tuck your tailbone, when you stand, you:

• Tend to inhibit the normal action of your abdominal muscles.

• Distort the curves of your cervical and lumbar regions.

• Compress your vertebral discs in an unhealthy way.

• Compromise the stability-creating disconnection between your sacrum
and pelvis.

• Displace your abdominal organs by moving them back and down.

• Interfere with your breathing.

Tadasana (Mountain Pose)

Distorted breathing is one of the simplest effects to experience in this pose. Try this: Stand in Tadasana (Mountain Pose). Now tuck your tailbone. Sometimes teachers suggest “dropping your tailbone” or “letting your sacrum move down.” These statements are what I call “sneaky tucking” because they sound innocent but actually are just other ways to say “tuck your tailbone.”

Mountain pose. Tailbone tucked.

Now, in Tadasana with your tailbone tucked, try to take a deep breath. It’s hard to breathe well this way. That’s because you have moved away from neutral (a normal curve) in the lumbar spine and into flexion. Flexing the lumbar spine interferes with the excursion of the diaphragm—the key muscle of breathing—because the diaphragm is attached to the lumbar spine at the L1 vertebrae, or top of your lumber spine.

Mountain pose. Pubic bone toward feet.

Now, instead of tucking, move your top thighs back so 2/3 of your weight is on the back 1/3 of your feet. Slightly internally rotate your thighs, and invite your pubic bone to move down toward your feet. This is the opposite of tucking and encourages the natural shape of your spine. Do you feel taller? Does your head seem to float above your body? Do you feel your shoulder blades dropping down? Do you notice that the shoulder blades are in a vertical line? 

See also 5 Steps to Master Tadasana

Seated Poses




Sukhasana Variation - Easy pose


Virasana Variation. Hero pose.

Take a Seat

You can also bring the principles of Tadasana into the sitting position you use for meditation. I have long practiced and taught that to sit comfortably, you must begin by creating a 120-degree angle between your trunk and femurs (thigh bones). This means you need to sit elevated on the corner (not the edge) of a cushion or small stack of blankets, letting the thighs drop more easily below the rim of the pelvis. If the angle is less than 120 degrees, the pelvis could easily tip back, disturbing the spinal column. If that happens, the lumbar spine is in flexion, and your posture won’t be as stable or comfortable.

See also Essential Foot and Leg Anatomy Every Yogi Needs to Know

Sukhasana (Easy Pose)

Now try this: Sit on the corner of several stacked blankets and make sure you are high enough for your thighs to release down. Be sure to elevate your pelvis—not your thighs. If you elevate your thighs and your pelvis, there is little difference between this position and sitting on the floor without blankets.

Now find a comfortable crossed-leg position. Sit slightly forward of your sitting bones. This engages your iliopsoas, which is contracting to pull your lumbar spine forward into a normal lumbar curve. originates from the bodies of the 12th thoracic vertebra and all five lumbar vertebrae. It joins with the iliacus to insert on the lesser trochanter of the medial femur. When you walk, the iliopsoas initiates the action of bringing the thigh forward; in other words, it initiates hip flexion in walking. The iliopsoas therefore has a lot of endurance because we use it so much every day; we can walk for hours. It’s the best muscle to keep you upright in a meditation seat.

If you instead sit behind your sitting bones, you will slump, and very quickly your paraspinal muscles, which run vertically along either side of your spine, will work too hard trying to hold you up against gravity, fatiguing quickly. The paraspinal muscles are more efficient at extensions (backbends) like Bhujangasana (Cobra Pose).


See also Anatomy 101: Why anatomy training is essential for yoga teachers

Next, take your attention to your pubic bone, and roll it toward the floor. The iliopsoas is the muscle you use to do this too. This action is the opposite of tucking. The downward roll immediately brings your pelvis into a neutral position and thus your spine into its normal curves. Be sure to make this distinction: Roll the pubic bone down between the legs; do not push the spine or pelvis forward. Pushing the spine or pelvis forward uses back muscles instead of the iliopsoas.

Finally, place your hands on your top thighs so the little fingers rest on the thighs, the palms facing your abdomen and close to it. Keep the elbows a little distance from the sides of your body. Drop your shoulders. Imagine that your pubic bone and breastbone are moving apart. If sitting crossed-legged is uncomfortable, try sitting on a yoga block in Virasana (Hero Pose) instead. Let your thighs find their own natural distance; you don’t have to hold them together. Notice how you are creating a triangle with your thighs and your pelvis. This is your base of support. Roll the pubic bone down to draw the spinal column inward and upward, establishing the normal curves.


To meditate, very slightly drop your chin and take your attention to a spot you can imagine is at the very center of your brain. Either close your eyes or let them stay half open, gazing about 18 inches ahead on the floor. Take a few soft breaths, and let your mental focus and bodily sensation lie gently on the breath. Does the position create the meditative state or does the meditative state create the position? I think both happen at once.

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The pelvis is the pot out of which the spine grows. When the pelvis is balanced, the spine is free and long with its normal curves. Think of this position of meditation as one that allows you to come home to yourself physically, mentally, emotionally, and spiritually. True balance is the expression of your natural wisdom. Let your spine express its natural wisdom in standing and sitting by always honoring your natural curves.