Text Neck and the Curse of Thoracic Dysfunction

Thoracic spinal or mid back pain is a common complaint among a wide range of age groups within the general population, with adolescents and the elderly alike reporting pain. Shoulder biomechanics can be affected due to restrictions in movement in the thoracic spine leading to narrowing of the subacromial space⁽¹⁾. Therefore, when patients complain of shoulder pain, clinicians should also consider the possibility of thoracic spine dysfunction, and assessment of the thoracic spine is recommended.

Background

It is widely acknowledged within the literature that thoracic flexion or also referred to as kyphosis is a factor in reduced shoulder range of movement⁽¹⁾. However, researchers from the University of Limerick, Ireland, stated that increased kyphosis of the thoracic spine may not be a factor to reduced shoulder range of movement⁽²⁾. The authors stated that further research of a higher quality is warranted.

When discussing reduced thoracic range of movement, there are a multitude of factors to consider. This region of the spine is the support structure for the ribs and breastbone, as well as the many vital organs the thorax protects. The volume of research and level of understanding of the thoracic spine is relatively less well researched in comparison to the lumbar and cervical spines⁽²⁾.

A position we frequently find ourselves into is that of cervical neck flexion leading to an increase in thoracic flexion. This is due to a recent and growing phenomenon dubbed ‘text neck’. It’s a common site now to see athletes and non athletes walking, sitting, standing looking downwards at a smartphone texting or reading, and it is essential to draw attention to this as health practitioners.

This posture leads to increased stress within the cervical spine, causing protraction at the shoulder girdle and increased flexion of the thoracic spine. Researchers from a Spine Surgery and Rehabilitation department in New York investigate biomechanical forces⁽³⁾. They found that the head weighs approximately 10-12 pounds, and as the head leans forwards, the forces at the neck increases to 27 pounds at 15 degrees of neck flexion, 40 pounds at 30 degrees, 49 pounds at 45 degrees and 60 pounds at 60 degrees.

Figure 1 demonstrates not only changes in neck flexion angles but also the changes within the thoracic spine when using a smartphone. It can be suggested that the longer someone maintains neck flexion, the more the more muscles fatigue and the greater the increase in neck flexion that occurs. With the volume of phone usage in modern times it is plausible that the positions developed from phone use carry over into the work station and sporting arena, and therefore may become a major player in the onset of back dysfunction and associated injury onset.

Researchers from Daegu University, Korea, not only looked at the effect of smartphone usage on posture but also looked at the effect on respiratory function⁽⁴⁾. Fifty participants were separated into two groups of 25 with one group using a smartphone for less than four hours per day and one group using a smartphone for greater than four hours per day. They measured peak expiratory flow, scapula positioning by looking at shoulder protraction and the craniovertebral angle also known as the forward head posture.

The results showed that significant differences existed in terms of posture at both the neck and the shoulder. They also showed a reduction in peak expiratory flow in those using a smartphone for longer than four hours per day. Slumping postures can inhibit the diaphragm and increase the activity of the scalenes promoting the forward head posture and trunk flexion⁽⁵⁾.

Anatomy and biomechanics (see figure 2)

To achieve shoulder elevation at 180 degrees, a number of joints need to accommodate sufficient movement to occur. These include the acromioclavicular joint, sternoclavicular joint, glenohumeral joint and the thoracic spine⁽¹⁾. Scapular position is largely determined due to the orientation of the thoracic spine; therefore if a patient has an increased kyphosis, then shoulder elevation can be implicated.