What Spine Type are You?

Sagittal (from the side) alignment of the spine is an incredibly important consideration in Schroth therapy. In fact, before we get to learn anything about scoliosis in our Schroth courses, we must first master the sagittal plane of posture.

This sagittal plane is also critical to surgeons, and surgical decision-making. Pierre Roussouly, a French Spine Surgeon, contributed greatly to his field in 2005 when he developed a classification system of sagittal spinal alignment.¹

Roussouly examined 160 people via x-ray with no history of back pain. He wanted to know if there was natural variety of spine shapes, and his hunch was correct: there is.

So many people in the field of spine health benefit from this classification system², including us, your Schroth Physical Therapists. 

There are four type of sagittal spinal alignment, all considered “normal” anatomically. 

• Type 1: Long Kyphosis, Prevalence = 5%

• Type 2: Flatback, Prevalence = 23%

• Type 3: Well Balanced, Prevalence = 47% (majority of humans)

• Type 4: Hyperlordosis, Prevalence = 25%

Roussouly Classification System

Just as Roussouly’s system helps surgeons make decisions about surgery, it helps us Schroth Physical Therapists make decisions about exercise prescription. Our patients with Type 1 spines get much different exercise instruction than our patients with Type 4 spines. 

Schroth is all about creating customized, specific exercises based on both sagittal alignment and scoliosis - much different than in a fitness class when every person in the class, regardless of spine type, is being told to do the exact same thing.

Type 1 Spines: Long Kyphosis

Just 5% of the human population has this spine type, making it the minority by far. The reason it’s dubbed “Long Kyphosis” is because of an 80:20 ratio of thoracic kyphosis to lumbar lordosis. (If you keep reading, you’ll realize that Type 3 spines, which make up the majority of the human population, have a 50:50 ratio.).

In type 1, the forward curvature of the thoracic spine (i.e. kyphosis) extends all the way down to the 3rd lumbar vertebra! In physical therapy school, and again in my Schroth training, my professors and classmates noticed a few large, protruding vertebrae in the junction between my thoracic and lumbar spine. One of them joked I had “Dino Vertebrae”. Another peer worried something was wrong with my back. My wise Schroth teacher came over and simply said, “Nope, nothing wrong, that’s just her anatomy.” Phew. She was acknowledging that I had a Roussouly Type 1 spine, and that’s A-ok.

Note that the sacrum, the bone below the last lumbar vertebra, is positioned quite vertically. This positioning dictates what’s called the sacral slope, an important measurement in surgical decision-making. As therapists, we’re more interested in the positioning of the sacrum (vertical versus diagonal versus nearly-horizontal.)

Exercise Considerations for Type 1 Spines:

Sometime around 2016 I took a consistent weekly yoga class in D.C. with a wise teacher named Siobhan. I had been practicing yoga for many years at that point, was a yoga teacher myself, and also a physical therapist. Despite having all of that training, Siobhan taught me an invaluable lesson during my tenure with her. As she led a roomful of yogi’s through a moderately-paced class, she came around and made adjustments to our bodies. Without fail, whether I was in a warrior 1, crescent lunge, or a tree pose, she would come over, wrap her hands around my hips, and lift my pelvis into an anterior pelvic tilt, which can also be described as encouraging me to lift my tailbone, or even more to the point: stick my butt out. Never in my life had any fitness instructor wanted me to do anything with my pelvis except tuck it under into a posterior pelvic tilt. It took many, many classes with Siobhan with her persistent adjustments for my dense brain to connect the dots: in order for me to get to a neutral spine with my Type 1 anatomy (read: vertical sacrum), I must anteriorly tilt my pelvis. I have no business doing a posterior pelvic tilt! No thank you, not for me. And once I made this connection and began deploying anterior pelvic tilts in all areas of my life, my posture improved, as did the strength in my hips and spine. The body works best in neutral spine, so it’s very important to know how to get there.

Caroline demonstrating Swayback Posture

One last exercise consideration for Type 1’s: the dreaded swayback posture. I am 100% guilty of this posture, so I feel I can trash talk it. Before becoming a Physical Therapist, (I hate to admit this) I stood in swayback all the time. My hyperflexible joints and Type 1 spine allow me to do this: I hyperextend and lock out my knees, let my pelvis sag forward, and slump my upper back backwards: an unbelievable feat of remaining upright with ZERO muscle activation. I am simply hanging on my knee, hip, and spine ligaments when I do this. Sound healthy? If you catch me standing like this, call the Schroth police...

But seriously, if you’re a Schroth therapist, a general physical therapist, or someone living in a body like this, it’s imperative to stop the swayback: unlock the knees, anteriorly tilt the pelvis, elongate the spine and get the shoulders to stack directly over the hips rather than behind them.

Type 2 Spines: Flatback

Type 2 spines make up 23% of the population. The kyphosis:lordosis ratio is 60:40 (again, the context is that Type 3 spine’s have a ratio of 50:50). What you’ll notice about this spine type in relation to the others is a lack of sagittal curvature; not as much thoracic kyphosis nor lumbar lordosis. From the side, these peeps don’t look very curvy.

Exercise considerations for Type 2 Spines:

Many of the same rules apply from our Type 1 Spines, but less extreme. Whereas a Type 1 spine may need to really lift the tailbone to anteriorly pelvic tilt, a Type 2 spine can get away with a “mini-lift” of the tailbone. 

Type 3 Spines: Well-Balanced

Definitely the most flatteringly-named spine type, this makes up the majority of the human population, at 47% prevalence. The kyphosis:lordosis ratio is 50:50. The sacrum is diagonally positioned versus Type 1’s and 2’s vertical nature. These folks naturally rest in an anterior pelvic tilt.

Exercise Considerations for Type 3 Spines:

Although you’d think life would be easy-peasy for the “Well-Balanced” crew, classic muscle imbalances can abound with too much desk-work or other types of prolonged sitting. 

Dr. Vladimir Janda, a Czech physician and researcher, defined Upper and Lower Crossed Syndromes³ in 1979, syndromes that many (including me) still use today to describe muscular imbalances.

Upper Crossed Syndrome and Lower Crossed Syndrome

We will discuss the syndromes in further depth in the Spine Type 4 Exercise Considerations section, as Type 4’s are much more susceptible to these imbalances.

Type 4 Spines: Hyperlordosis

Making up a good part of the human population at 25% prevalence, Type 4 spines are very curvy from the side. Excessive thoracic kyphosis and moreso, excessive lumbar lordosis is hallmark. The sacrum is positioned almost horizontally in this demographic. These people rest in a large amount of anterior pelvic tilt, or “butt-out” position. I’ve had patients with this spine type tell me that parents or peers compared them to a duck early in life (and although in some cases that can be psychologically painful, it does aid in giving a visual to what Type 4 spines look like.) 

Exercise Considerations for Type 4 Spines:

Type 4 spines are very susceptible to Dr. Janda’s Upper Crossed Syndromes and Lower Crossed Syndromes due to the exaggerated spinal curves.

In a nutshell, these individuals will need to stretch their pectorals, cervical extensors, hip flexors, and lumbar extensors, while simultaneously strengthening their cervical flexors, thoracic extensors, abdominals, and glutes, just to create balance.

These are the folks who will benefit tremendously from “tucking their tailbones under” during exercise, to compensate for the large lumbar lordosis.

Big Picture: Why does this matter for scoliosis treatment?

We know that most humans fall into Type 3 and Type 4 sagittal spinal anatomy (combined, that’s 72% of all people). Far fewer fall into the Type 1 and Type 2 categories (28% combined). While general physical therapists and fitness instructors are catering to the majority (Type 3’s and 4’s), most people with scoliosis are in the minority sagitally: they have Type 1 and Type 2 alignment. Not all, but most. And unfortunately those type 1 and 2 people are getting the wrong cues for exercise in the general arena. Very popular methods of exercising – Barre, Pilates, some yoga classes – revolve around the posterior pelvic tilt – it's ubiquitous in those types of classes. (For further reading about this exact topic, read our blog about lumbar scoliosis and pelvic tilting.) 

Knowing what spine type you are can revolutionize your strength, stability, and muscular balance. It can profoundly boost your confidence during exercise and remove the fear of getting injured: if your form is good, and a big part of form is being in neutral spine, injury is much less likely.

If you haven’t paid us a visit in person yet, please do. You’ll find out your spine type on day 1 during your evaluation. Let’s unlock your best, bespoke exercise plan, for life.

References:

1. Roussouly P, Gollogly S, Berthonnaud E, Dimnet J. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine (Phila Pa 1976). 2005 Feb 1;30(3):346-53. doi: 10.1097/01.brs.0000152379.54463.65. PMID: 15682018.

2. Philippi M, Shin C, Quevedo S, Weiner J, Chavarria J, Avramis I, Rizkalla JM. Roussouly classification of adult spinal deformity. Proc (Bayl Univ Med Cent). 2024 Apr 11;37(4):688-691. doi: 10.1080/08998280.2024.2334548. PMID: 38910817; PMCID: PMC11188786.

3. Janda V. Die Bedeutung muskulärer Fehlhaltung als pathogenetischer Faktor vertebragener Störungen [The significance of muscular faulty posture as pathogenetic factor of vertebral disorders]. Arch Phys Ther (Leipz). 1968 Mar-Apr;20(2):113-6. German. PMID: 5728906.