Understanding Spine Anatomy: Your Guide to the Low Back

Let’s talk about the anatomy of the spine. We’re going to approach it in a, hopefully logical, way. Starting with the deepest layer – the skeleton - and then building up to discuss the role of the muscles, fascia etc.

Because if you’re struggling with issues with your low back, understanding spine anatomy is an important first step. From the lumbar spine, naturally the one I tend to talk about the most, through the thoracic and cervical areas of the spine. We’ll talk about the make up and function of this important part of the body.

Helping you to ultimately reduce the risk of further injury and find solutions to help recovery.

Understanding spine anatomy: the basics

The spine, as you probably remember from biology textbooks at school, is made up of 33 individual bones or vertebrae. These are stacked on top of one another, separated by intervertebral discs, which act as shock absorbers and prevent the vertebrae from rubbing against one another.

Surrounding this structure we have fascia and ligaments. These give the spine basic stability, holding the vertebrae lightly in place and allowing for a specific range of movements. 

Ligament damage and ‘ligament creep’

Have you ever heard the term ligament creep? It’s the process whereby soft tissue, or ligaments are able to gradually stretch, or lengthen, over time. The more time you spend with a flexed spine, the more the ligament will learn to stay in that lengthened position. We see this often in the neck area, creating a forward head posture from hours of being hunched over a computer, phone or mobile games console.

Unfortunately ligament damage, or ligament creep, over time, can impair how well these tissues are able to stabilise the spine. This can lead to the spine retaining an abnormal position, potentially resulting in pain and dysfunction.

The muscles of the spine

When our goal is understanding spine anatomy from the point of view of the muscles, it’s useful to start with the deepest layer of musculature that surrounds the spinal column. This is made up of:

Intrinsic back muscles – the deep ones

• Multifidus – a series of narrow muscles that run up either side of the spine. These function to stabilise the spine, particularly in the lumbar region.
• Interspinales muscles - these attach, between adjacent vertebrae, to the spinous processes – the nobbly bits of your spine you can feel when you round your back.
• Intertransversarii muscles - these go between transverse processes – the nobbles on the sides of your spine.
• Transversospinales muscles – these link the previous muscles and support rotation and extension of the vertebral column.

Anatomy of the spine – the mid-layer muscles

Next, we look at some of the mid-layer of muscles, whose function is to support stability – these are not necessarily movement muscles.  

• Quadratus Lumborum is actually located right at the back of the abdomen. This is the muscle that brings the pelvis, the lumbar spine and the ribs together.
• Psoas is an influential muscle. It’s a hip flexor that adjoins L5 L4 L3 L2 L1 with bits that go up into T12.
• Transverse abdominis is a deep abdominal muscle that wraps around the torso from the spine all the way around the front. Beneath it lie the pelvic floor muscles.
• Longissimus and Iliocostalis – part of the erector spinae group, or spinal erectors.

Understanding spine anatomy – the superficial back muscles

These are some of the major muscles in the back, that sit just below the skin, their role is to support bending, stretching and rotation movements.

• Latissimus dorsi is a spine stabiliser.
• Thoracolumbar fascia wraps it all together – these are superficial muscles that join into the thoracolumbar They are crudely shaped like a diamond, sitting over the lower back. Lots of the other muscles join into it. These also attach to the spinous processes, contributing to spinal stability.

Abdominal muscles that support the spine

• Internal and external obliques – these assist in rotation movements of the trunk, and in the case of the large external obliques, lateral flexion.
• Rectus abdominis on the front, is known as the six pack
• Abdominal fascia which is similar to the thorum fascia but around the front.

Look out for future videos and blogs where I’ll be looking at the function of these muscles and how they work together. As well as how to avoid issues and injury and use your understanding of spinal anatomy to aid low back pain recovery.

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