The entire spine has the ability to flex, extend, rotate, and laterally flex (side bend). Each segment of the spine has varying degrees of motion depending on the structure of the vertebrae and surrounding structures (like ribs vs. no ribs attached to it). The spinal column is actually made up of 5 parts: Cervical(neck), thoracic(mid back/rib cage), lumbar(lower back), sacral(between the pelvis), and coccyx(tailbone), but we often only refer to the first 3 as the “spinal column” because the last two are fused together. There are 24 vertebrae in the cervical, thoracic, and lumbar spine. There are 5 fused sacral vertebrae and a varying number of fused coccygeal vertebrae (remember the tail in the movie Shallow Hal?).
Flexion of the spine is rounding the spine forward (like a @Gymfuckery deadlift). Extension is bending the spine backward (think Exorcist). Lateral flexion is side-bending. Rotation is rotation. The lumbar vertebrae primarily flex, extend, and side bend (they rotate a little bit). The thoracic spine primarily flexes and rotates and has a little bit of extension and side bending. The cervical spine is proficient in all ranges of motion, but as Mike asks at the end of the video, there is one specific part of the cervical spine that does most of the rotation.
The glide that Mike refers to is called “translation” and is essentially side-bending (lateral flexion) of the spine in opposite directions and in two places at once. If you glide to the right, the vertebrae below the apex of the glide are side bending to the right and the vertebrae above the apex of the glide are side bending to the left. This makes it look like the spine is staying “neutral” as it “glides” side to side. Katie has some work to do to be able to do this proficiently. The spine can also translate forward or backward and is a combination of flexion and extension.
Why should you know this stuff? Improve the ranges of motion in each area of your spine and it will likely feel pretty fucking awesome. Rotation is often limited in people’s workouts… so do it!
