3 - Hold Steady - Information

Goals Information Skills Drills Questions Review

 Information to Master

As you learned in Session Two, the neutral position is vital to spine health. Achieving this posture while sitting or standing is one thing. It's another to know how to coordinate the muscles of your trunk and abdomen in order to support and stabilize your spine during daily and work activity. This session will give you an in-depth look at the anatomy of the spinal stabilizers. Then you'll begin to put key muscles of the back and abdomen to work during exercise and activity.

Before jumping ahead, spend time recalling what you learned in Session Two. Review the answers to last session's Questions for Review.

 Answers for Review

In the last session, you were asked three questions. Take a few moments to compare your answers to those given here.

1. What is a spinal segment?

A spinal segment includes two vertebrae separated by a disc, the nerves that leave the spinal cord at that level, and the small facet joints that link each level of the spinal column.

2. What is the neutral spine position?

The neutral spine position is a comfortable back posture that is between the extremes of spine flexion and extension. In general, this middle position is a slight inward curve in the small of the back.

3. How do the natural curves of your spine relate to the health of your back?

The natural curves place the spine in a centered position, one that helps avoid extra strain on the parts of the back. The natural curves of the spine position the muscles where they work the best. Good posture and optimal muscle function protect the spine from small amounts of damage that could otherwise add up to back pain and problems.

What is Spinal Stabilization?

The body's ability to properly align, hold, and guide the spine is called spinal stabilization. This does not mean holding the spine rigid. Rather, spinal stabilization is the body's way of controlling and guiding the spinal joints as they move. The mobile parts of the spine are steadied so that no harmful shifting or sliding happens within each spinal segment.

The body relies on many tissues, including nerves, ligaments, and muscles, to produce spine stability. Without support from these stabilizers, the natural curves of the spine would collapse. In this section, you'll learn the anatomy that affects spinal stability.

Why is Spine Stability Important?

As you discovered in Session Two, the spine works best and stays healthiest when it is centered in the neutral spine position. This balanced alignment reduces day-to-day strains on the parts of the spine. The strains from using poor spine postures cause small amounts of damage in the parts of the spine. You may not feel that anything is wrong. But with time, these small amounts of damage add up and may eventually cause back pain and problems.

The same thing can happen if your back isn't steady and stable as you go about daily activities. Consider the loads affecting your spine as you walk, sit, twist, lift, or carry. These actions place a demand on spinal tissues. If the spinal stabilizers are not doing their job, the loads put extra strain on the parts of the spine. This is because the spinal segment is free to shift and slide subtly. These subtle movements are not often painful. But scientists believe the wear and tear they cause can take a toll on the parts of the spine.

Anatomy of a Stable Spine

Spine stability starts with optimal alignment. Recall that the spine has three natural curves, with the low back slightly curved inward. Aligning the low back in the neutral position (between the extremes of flexion and extension) creates a stable spinal column, one that can tolerate greater loads without buckling. Spine stabilization relies on this "power position" of the low back.

You've now learned how to position your spine in neutral. The next step is to understand how the parts of your body work to keep your spine stable as you move. Safe spine movement relies on key stabilizers of the spine. These stabilizers include:

  • Ligaments
  • Fascia
  • Muscles
  • Nerves

Ligaments

Ligaments are rope-like bands of tissue that connect bones together. Most ligaments are lined up to keep joints from bending the wrong way. This feature creates stability for the joints. There are many ligaments that support and protect the joints of the low back. Several long ligaments connect on the front and back sections of the vertebrae. Smaller ligaments join one vertebra to the next. Thick ligaments also connect the bones of the low back to the sacrum (the bone below L5) and pelvis.

The disc (described in Session Two) also works like a big ligament. Recall that the nucleus is centered within the disc. It is surrounded by the annulus, which is a series of ligament rings. A healthy disc limits motion within the spinal segment.

Fascia

Fascia is similar to ligaments, but fascia is more like a sheet than a rope. Fascia covers and connects muscles and organs. A large diamond-shaped sheet of fascia covers the low back. This crucial stabilizer of the lower spine is called the thoracolumbar fascia (TLF). Many large and important muscles connect to the TLF. As these muscles work, the TLF pulls tightly to the low back, keeping the lumbar spine from bending out of the neutral position. Because it surrounds the back muscles, the TLF also augments the power generated by these muscles.


Muscles

Spine stabilization relies on the controlled actions of many important muscles. Because of their location toward the center of the body, and because of their importance in spine stability, these key stabilizers are called "core" muscles.

Core muscles help grip and hold the spine. They keep each spinal segment from shifting and sliding as you do your activities. The two main core stabilizers are the multifidus and transverse abdominal (TA) muscles. Knowing where these muscles are and how they work is essential as you learn ways to stabilize your spine.

The multifidus muscles are small back muscles along each side of the spine. They come in different lengths. Some cross only from one vertebra to the vertebra below. Others cross two, three, and up to five spinal segments. In the lower spine, the multifidus muscles go from the lumbar spine to the sacrum. Although small, the multifidus muscles connect directly to each spinal segment, making them one of the most important muscle stabilizers of the spine.

The TA (transverse abdominal muscle) is a thin, belt-like muscle that wraps around the low back and abdomen. Think of this muscle as a girdle around your waist. As it contracts, the TA draws the lower abdomen inward, much like would happen if you were zipping up a tight pair of jeans.

Notably, this muscle anticipates your every move. The TA actually kicks in to steady the spine even before you lift an arm or leg. Scientists call this a feed forward loop. Nerves to the TA alert the muscle in advance of your movement, giving it a split-second advantage to grip and protect your spine. The TA's feed forward loop normally works like this. You go to grab a gallon of milk from the refrigerator. Just before you reach out your arm, your nerves signal the TA to contract. Even before you lift the milk container, your TA has already begun to engage and stabilize your spine.

Other muscles are needed for spine stability. Recall that many large and important muscles attach to the diamond-shaped sheet of fascia called the TLF. As these muscles contract, they pull the TLF tight to the back, keeping the spine in its power position. The latissimus dorsi muscles (the "lats") attach to each side of the top of the TLF. From there, they angle upward along your back and the sides of your upper trunk. The gluteus maximus muscles (the largest of the buttock muscles) connect to the lower sides of the diamond, giving the buttock and hips a solid connecting point to the TLF.

Two important abdominal muscles also connect to the TLF. One, mentioned earlier, is the TA. The other is the back portion of the internal oblique abdominal muscles. Training each of these key stabilizers is an important feature of your recovery - and of the future health of your spine.

Nerves

Smooth, guided spine motion is a mark of a stable spine. Through normal nerve function, key muscles are able to keep the spine in its neutral position. These motor nerves signal the key muscles to grip and hold and to guide and control the spine. If the signals are not coordinated, the muscles cannot do their work to help stabilize the spine. Back pain can interrupt these signals and stop the key muscles from stabilizing the spine.

Nerves also carry information back to the spinal cord and brain. These sensory nerves transmit sensations such as heat, cold, touch, pressure, and pain. They also give us our sense of position. Position sense tells us about our body's position. It is an essential part of the way we control our movements. Information from sensors in the skin, ligaments, tendons, muscles, and joints is sent to the brain and spinal cord about the location of our joints. We rely on position sense to locate the neutral spine position. A deficiency in our awareness of position leads to small errors in position sense and movement control, which can overload the soft tissues in the spine. When the lumbar spine can't find or keep its neutral position, movement of the spine takes place toward the extreme ends of motion rather than in the middle.

Anatomy of an Unstable Spine

How does a spine become unstable? The most obvious cause is a bad accident that tears the ligaments that support the spine. But years of poor posture and movement can also stretch spinal ligaments so that they can no longer steady the spine. An injured disc allows extra movement within the spinal segment and may create an unstable segment. Diseases that affect the supportive structures of the spine can also cause instability at one or more levels of the spine.

Altered function in the core muscles upsets spinal stability. The TA and multifidus muscles work together to grip and hold the spine, almost like an on-off switch. Back pain short-circuits this switch, and the core muscles stop working normally. The multifidus muscles that cross the problem area of the spine become sluggish and begin to shrink (atrophy). The TA shuts down, too. Its actions are no longer coordinated. When the TA and multifidus muscles are not functioning, the spine is left unprotected against daily strains.

Scientists have learned that even one instance of back pain can alter normal function in these two important core stabilizers. The problem is intensified in people with chronic back pain.

Ways to Stabilize the Spine

When the spine is unstable, there are only a few ways to make it stable again. The most dramatic way to create stability is by lumbar fusion, a type of back surgery that uses bone grafts and metal hardware to bind one or more spinal segments together.

A less invasive choice is a flexible back brace. Clinicians are generally not keen on issuing braces like this, however. Scientific studies have not proven that they work all that well. Such braces can help early in a course of back pain and are sometimes recommended when back pain first strikes. They are occasionally used when the back needs some added support. In these cases, they bind the back and abdomen, keeping the lower spine from extra movement. They also give patients a reminder of proper body alignment and posture.

Patients who need additional lumbar stability may benefit from a flexible back brace while doing challenging activities, such as heavy lifting, hiking, and raking. However, healthcare providers will usually only issue a brace with clear instructions to remove it often to do exercises for the back and abdomen. Otherwise, these key muscles begin to rely on the brace and may begin to atrophy and weaken. Another drawback is that these braces may give a false sense of strength and security that could lead a person to over-do and possibly end up causing more damage.

A third option to support and stabilize the spine is exercise - but not just any exercise. The exercises designed to improve spine stability are often called core stabilization exercises. There are many variations of core stabilization exercises. In general, they usually start out easy and become more challenging as you progress. Patients who do these exercises often report improved pain control, mobility, and function.

Goals Information Skills Drills Questions Review






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