Have you ever seen an image representing a standard or ideal postural alignment, a person standing erect with perfect symmetry? Images such as this are commonly used to illustrate postures in which body parts are least stressed; they are often used as a posture to which we should aspire for aesthetic reasons.

Yet the importance of posture may have changed since Victorian times. An aesthetically pleasing posture may be inherent to activities such as dressage or ballet, but few people today strive for good deportment. The well-being of children is as important now as ever, yet teachers are less likely to instruct pupils to sit up straight; and if teachers do tell pupils to sit up straight, it might be a means of retaining attention rather than an attempt to improve posture. Nevertheless, from an anatomical standpoint there are good reasons to consider changing body postures that vary significantly from this ideal. Let’s take some aspects of the body and consider the consequences of malalignment to each. As with most of the postures described in this book, the consequences of prolonged alteration in posture to a particular region can only be postulated. In addition to the material provided here, each of the 30 postures in chapters 3 to 10 includes a Consequences section in which you can learn more about the consequences of malalignment to that specific posture.

Bones

When weight-bearing long bones develop with greater curvature than normal, the normal stresses and strains acting on them change. Looking at figure 1.1 consider the tibia of this person’s right leg. Compressive forces increase on the concave side of the tibia, whereas tensile forces increase on the convex side. In this example the increased compression is not just on the medial side of the tibia but is also on the anterior aspect (the concave regions of the bone in this example), and the increased strain is not only on the lateral side but also on the posterior of the tibia (the convex regions of the bone). This is because in this person the tibia is bowed not only laterally (figure 1.1a) but also posteriorly (figure 1.1b). If you are not sure that you can see this, take a pen and, using figure 1.1a, trace a line down the centre of the person’s right leg, bisecting it longitudinally from the thigh. Notice how your line curves outwards, towards the margin of this book, as you attempt to bisect the calf. The weight of this person is not transmitted optimally through his tibia, nor is the force that is transmitted up through his leg when his feet strike the ground in walking. Because bones are living structures capable of deformation, suboptimal weight bearing through a long bone in this manner could lead to further deformation and therefore a less pleasing appearance for the person. But as stated at the outset, this book is not about changing posture for aesthetic reasons. Why should we bother with a bowed tibia, anatomically speaking? One reason is that a long bone shaped in this manner has reduced load-bearing capabilities and increased risk of injury through, for example, stress fractures. Bowing in a long bone also leads to a change in the immediate joints associated with the bone, in this case the knee (tibiofemoral, patellofemoral and tibiofibular joints), ankle and possibly even joints more remote from this, such as the hip and sacroiliac joint. Overall, the consequence of malalignment is that the bone itself and joints associated with it will not function optimally. The result could be pain in the bone, joints or associated muscles.

Figure 1.1 Tibia in this person is both laterally and posteriorly bowed, as shown in posterior (a) and lateral (b) views. Arrows indicate that compressive forces are increased on the concave side of the bone, while tensile forces are increased on the convex side of the bone.

Muscles

In the ideal posture, there is minimal strain on soft tissues. If the body is aligned in such a way that muscles remain either actively or passively shortened, they will adapt to their new position and there will be a decrease in the number of sarcomeres from their structure (Heslinga et al. 1995), a decrease in the length of sarcomeres (Spector et al. 1982) and a decrease in the length of tendons (Herbert and Balnave 1993). This is known as adaptive shortening and may mean that the muscle is less able to generate power. When muscles shorten, they hold joints together more tightly so there may be a decrease in the range of motion in that joint. Conversely, muscles that remain in a lengthened position add sarcomeres to their length and may weaken. This is known as stretch weakness. When muscles lengthen, they hold joints together less tightly. There may be an increased range of motion in that joint. Joints that are too stiff or too mobile could be more easily injured than joints functioning normally.

Anyone who has ever had to maintain a static posture for long will know that muscles quickly develop tension and, if the position is prolonged, it can cause pain. Over time, trigger points may develop, and in chronic cases pain may persist despite a change in body position. The increase in muscle tone may at first be localized to the part of the body that is out of alignment, but as other muscles start to accommodate this dysfunction, the problem spreads. Muscles may fatigue more quickly—first locally, where they cross the affected joint, then distally—and eventually there may be global pain, often in regions distal to the initial site of dysfunction. In severe cases, function is impaired. For example, balance may deteriorate. Mechanical stress perpetuates trigger points; the most common source of this stress is asymmetry and skeletal disproportion (Travell and Simons 1999).

So, these could be the overall effects of malalignment for muscles:

• Increased likelihood of muscle weakness (due to shortening or lengthening of muscles)
• An increase or a decrease in range of motion in a joint
• Possible increase in the likelihood of injury to a joint
• Pain in the affected muscle and in muscles forced to compensate for dysfunction
• Impaired function

Joints

When a joint is not aligned, it also incurs increased stress. Observe the crease on the back of the neck of the person in figure 1.2. What do you think might happen to her cervical joints if she were to maintain this neck position for an hour? What if she maintained this posture all day, whilst performing a desk-based job, for example? Would that give rise to neck pain? What might be the consequences if she maintained the posture all day, every day, for a week? You might expect more frequent neck pain or pain of greater intensity or duration. What if this were the client’s normal posture, one that she had inadvertently maintained over many years? Is it reasonable to postulate that in addition to neck pain, there could be a decrease in synovial fluid in cervical joints and a decrease in range of motion at the neck as the joint capsules of cervical vertebrae adhere to local connective tissues? Could the long-term consequences be degeneration of cartilage and early degeneration in the joint? Degeneration would then impinge nerves, resulting in neck, shoulder, back and arm pain.

Figure 1.2 Example of a forward head posture.

Ligaments

When a ligament is kept in a lengthened position, it may creep, becoming longer. Longer ligaments provide less stability for the part of the joint that they cross. There may be an increase in range in that joint and even hyperextension of the joint. In figure 1.2, the anterior longitudinal ligament in the cervical region may be lengthened and the posterior longitudinal ligament shortened. This could impair the function of these important structures. Figure 1.3 shows a client with eversion of the ankles. There is increased compressive stress on the lateral side of the ankle and increased tensile stress on the medial side of the ankle. The medial collateral ligaments of the ankle have been overstretched over time, making this person prone to eversion injury (e.g., sprain to the deltoid ligament). Change in the length of a ligament may be minimal, yet if prolonged it will lead to altered biomechanics of that joint and of the joints above and below it. Injury to a ligament can also lead to postural change. Anterior cruciate ligament (ACL) rupture, for example, increases the risk of knee osteoarthritis, which is associated with genu valgum and varum postures. It is not known whether rupture of an important ligament such as the ACL predisposes a person to the development of genu valgum or varum postures.

Figure 1.3 Altered ankle alignment affecting ligaments of the ankle.

Lengthening of ligaments means not only is that particular joint less stable, but also the joints above and below it are too, because these joints become subject to additional stresses and strains. Therefore, someone with lengthened ligaments in the knee is at greater risk of hip and ankle injuries on the affected side, and someone with lengthened ligaments in the elbow is at greater risk of shoulder and wrist injuries on the affected side. Ligaments contain nerve endings that are important for reflex and proprioceptive function. Constant compression or tensioning of ligaments—rather than the normal varying of compression or tension as occurs during movement or weight bearing—may adversely affect function of nerve endings.

Other Soft Tissues

As with bones, joints, muscles and ligaments, a posture that results in increased compressive or tensile forces on soft tissues such as blood vessels, lymph vessels, nerves or fascia is likely to adversely affect how those tissues function. Have you observed what skin looks like when a plaster cast has been removed? Compressed beneath the cast, the skin appears pale and lifeless. You can observe this also on removal of an adhesive bandage, even when it has been worn for just a few days. Skin does not respond well to being permanently compressed, albeit lightly. The compression—or traction—of soft tissues within the body is not visible; such a condition may coincide with a prolonged alteration in posture, but these structures are likely to be as affected by malalignment as muscles, tendons and ligaments are.

Perhaps the most significant consequence of mal-alignment is that the 30 postures described in this book are each likely to worsen if not treated. The degree to which they worsen is likely to vary; some postures will worsen to a greater extent than others. For example, a person with a kyphotic posture can become increasingly kyphotic, but a person with a flatfoot posture cannot necessarily get a more flattened foot. How quickly a posture worsens is also highly variable. It may worsen within months or over many years, and the progression depends on many factors. Examples are the stage at which the posture is identified, the person’s underlying health, the availability of professionals able to provide advice and treatment and the willingness and ability of the client to engage in postural correction activities. Consider two sisters with a familial history of genu valgus, both having noticed that they too have a mild genu valgus posture in one knee. One sister continues to enjoy bootcamp-type exercise involving weightlifting and running and is unconcerned with her knee posture. The other sister seeks advice and learns that neither weightlifting nor running is favourable for the genu valgum posture. Weightlifting places excessive load through the malaligned joint, whilst running involves repeated impact. The second sister explores the many other sporting options available, such as non-impact activities like swimming and cycling and rowing, and uses some of the recommendations set out in this book for management of the genu valgum posture. It seems likely that the sister who engages in activity that is unfavourable to this posture is likely to have a worsening of the posture more quickly than her counterpart.

When a client comes to you for hands-on therapy, postural assessment is important because the advice you can give after early identification of malalignments can help a client to avoid aggravating factors and adopt exercises and treatments that minimise further disruption of the joint. More information on broaching the subject of postural correction is in chapter 2 in the section titled Gaining Rapport and Enhancing Engagement as well as the section in chapter 6 titled What You Can Do as a Therapist.

Excerpt from Postural Correction, Jane Johnson, ©2016

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