Mark Alexander explains how poor upper-back posture can set up an injury chain reaction
The thoracic spine and ribcage have extremely complex anatomy and articulations, and are commonly neglected in the injury management of spinal and peripheral sports injuries. Yet thoracic mobility and ideal posture are vital to injury prevention and recovery.
The thoracic spine has 12 vertebrae and is the most stable region of the spine, thanks to the limitations imposed by the structural elements of the ribcage and the vast array of ligamentous and muscular connections (1). The function of this relative immobility – and hence stability – is to protect our vital organs, such as the heart and lungs, but this has implications for the contribution of thoracic spine stiffness to sporting injuries.
The first to seventh ribs are classified as ‘true’ ribs, as they articulate directly with the sternum. The eighth to 10th are ‘false’ ribs, as they don’t articulate with the sternum but with costal cartilage, and the 11th an 12th are floating ribs as they have no sternal attachments at all (1). Use this classification only as a guide: there can be major anatomical variations between individuals.
Ribs 2 to 10 each articulate with the vertebrae above and below; and although variable, ribs one, 11 and 12 generally articulate with only one vertebra. Every rib articulates with its thoracic vertebra(e) via two joints, the lateral ‘costotransverse’ joint (which attaches to the transverse process) and the more medial ‘costovertebral’ joint (which attaches to the vertebral body).
The ligamentous connections between the ribs and the spine and sternum are extremely stable and provide for only limited motion. Because of this, movement in the thoracic spine, while possible in all directions, occurs only in small magnitudes.
Flexion/extension is more limited in the upper thoracic region; rotation/lateral flexion is more limited in the lower thoracic spine. Extension is limited by the ribs, anterior longitudinal ligament, contact of the spinous processes and articular facets and disc structure. Rotation is mainly limited by the ribcage (ribs plus cartilage plus articulations). The significance of these structural limitations increases with age.
There is a dearth of literature on links between the thoracic spine and sporting injuries but Harrison et al (2) showed that thoracic spine kyphosis (convex curve), which increases with posterior translation of the thoracic spine, may be linked with low back pain. Scapulo-thoracic crepitus and bursitis (pain and grinding underneath the shoulder blade) has also been linked with an increased thoracic spine kyphosis (3). Although there is no specific empirical evidence, anecdotally thoracic spine stiffness and kyphosis can be a common predisposing factor to upper-limb overhead injuries, as well as thoracic and low back pain.
A normal newborn has to have an extremely compliant chest wall, so that it can deform in order to exit the birth canal. It is mainly cartilaginous: ossification does not occur for several months after birth, and skeletal development does not cease until the 25th year with the growth of the rib tubercle.
With ageing, the costal cartilages ossify and allow less movement, and as the ligamentous and joint capsules stiffen, the thoracic spine loses mobility. The thoracic vertebrae commonly become anteriorly wedge-shaped, as the result of postural issues and/or osteoporotic vertebral collapse. This contributes to an increasingly kyphotic spine. Bone mass starts to deteriorate after the third decade, and although certain kinds of weight- bearing activity have been shown to reduce the rate of bone loss, roughly 70% of over-75s have osteoporosis of the ribs and spine.
The thoracic spine and chest wall have been shown unequivocally to become less compliant and mobile with age. The healthy thoracic spine has a natural kyphosis. This normal anatomical position is under threat as poor, prolonged slumped postures – the curse of modern day society – force the thoracic spine into further kyphosis, or structural hyper-kyphosis. Sportspeople are by no means immune. The vast majority are recreationally active and therefore as likely as their sedentary counterparts to be slumped and desk-bound for large parts of the working day. Even full-time elite athletes spend significant periods relaxing in the normal fashion: hunched over a computer game or the internet, or slouching in front of the TV. Pro cyclists and triathletes are particularly at risk as a direct result of their sporting posture.
A hyper-kyphotic thoracic spine rarely develops in isolation. As the curvature increases, there are accompanying anatomical consequences. In sitting, the cervical spine and head move forward. This causes excessive upper cervical extension and lower cervical anterior shearing, often creating neck pain and headaches (4). If treatment is only directed to the cervical spine and not at the thoracic stiffness causing the problem, symptoms may temporarily reduce but the pain will never go away.
Prolonged slumped sitting and thoracic hyper-kyphosis cause posterior pelvic tilting, which contributes to lumbar flexion or loss of lordosis. The prolonged positioning of the spine in thoracic kyphosis and lumbar flexion can contribute to permanent elongation of ligamentous and muscular tissue.
As time progresses, this hyper-kyphotic posture becomes chronic and the neural and connective tissue adaptations become difficult to remedy. Pain often accompanies chronic postural hyper-kyphosis because of micro-trauma inflicted on the posterior muscular, ligamentous and/or neural structures from prolonged stretching.
The spinal discs, especially in the thoracic and lumbar spines, may also be structurally affected: compressed anteriorly and stretched posteriorly, causing posterior annular degeneration and potentially disc bulges/prolapses, which can be devastating for the sportsperson. When standing, the hyper-kyphosis will remain and it is easy to observe the consequential pelvic, lumbar and cervical alterations. These, too, can predispose the individual to upper and lower limb conditions as they make adjustments to their biomechanics.
If the thoracic spine is held in hyper-kyphosis, the scapulae (shoulder blades) must also move in a relatively anterior-tilted, downward rotated and protracted position – a position linked with gleno-humeral impingement (5). The hypothesis is that as the scapula and hence the acromium move forward and downwards, the head of the humerus has less room to move under the acromium, which leads to micro-trauma of the supraspinatus and other sub-acromial structures, causing pain.
In sitting, the therapist can demonstrate the effect to their client by getting them to compare their range of shoulder elevation and pain first in an ideal upright posture and then in a slumped hyper-kyphotic posture. It is more than likely that they will have considerably less movement and greater shoulder pain in the slumped position.
In terms of the sporting population of swimmers, tennis players and golfers, any thoracic mobility restrictions they have will predispose them to shoulder pathology. This has implications for the assessment of all shoulder patients: it should be mandatory to assess the client’s thoracic extension and rotation to ascertain if thoracic stiffness is contributing to their condition.
Thoracic hyper-kyphosis is likely, also, to be linked to spinal and upper-limb conditions such as thoracic outlet syndrome (neurovascular compression), T4 syndrome (nonneurological numbness in the hands and arms) and Scheuermann’s disease (hereditary juvenile kyphosis), because of the consequent structural changes in the thoracic spine and positional changes of the scapula.
If there is a loss of lumbar lordosis because of the hyper-kyphotic thoracic spine and posterior pelvic tilt, the lower limb will be prevented from moving in an ideal pattern, which may predispose the individual to a variety of lower limb conditions. Hypothetically the motor patterning of the muscles that cross the pelvis and hip, such as hamstring, rectus femoris and adductors, may be altered, risking muscle tearing.
As the costal cartilages ossify and the kyphotic spine alters structurally and stiffens, reduced rib and spinal mobility will affect the normal movement of respiration, which is a rib ‘bucket handle’ effect. In older patients the result may be to cause or lead to worsening respiratory conditions. In athletes, it may lead to reduced tidal volume and VO2max, impacting on sporting performance.
Again, the therapist can readily demonstrate to their client the effect of poor posture. In sitting, compare their ability to take a deep breath in an ideal upright posture and then in a slumped hyper-kyphotic position. They should be able to breathe more deeply and freely with ideal posture.
If the thoracic spine has lost extension, the therapist needs to take active measures to reverse permanent structural changes. If this altered posture is the result of a disease state such as Scheuermann’s disease or osteoporosis, it is going to be impossible to restore normal spinal alignment, so the emphasis should be on postural advice and exercises to maintain the client’s mobility levels.
Where there is no underlying condition, the therapist should aim not just to restore mobility but also to ensure the client maintains ideal posture in the future. The most important aspect of re-education will be when the patient is sitting. Strategies for this are:
Gentle extension exercises (see figs 1 and 2) can initially be performed once a day, in static lying, using:
The support should be placed at each vertebral level in turn for 20 to 30 secs. As the client’s toleration improves, the exercises should be performed two to three times a day. An alternative would be to arch back over a chair or Swiss ball.
It is easy to overlook thoracic spinal stiffness when a client presents with shoulder problems (especially in athletes), but assessment of the thoracic spine should be an integral part of the sports therapist’s initial examination.
Aim always to restore mobility and provide the necessary exercises and long- term postural re-education to ensure that the client retains ideal posture in the future.
Mark Alexander is the physiotherapist to the Australian Olympic and Commonwealth Games Triathlon team. He has worked with Wasps Rugby Union and London Broncos Rugby League teams and toured with Riverdance, the Irish dance troupe
Illustrations by Viv Mullett