Anatomy, Biomechanics and Regional Interdependence of the Thorax
Top Contributors - Jess Bell, Lucinda hampton and Merinda Rodseth
Introduction[edit | edit source]
However, between 36 to 41 percent of individuals who present with neck or back pain will also have thoracic pain (i.e. around 4 in 10 patients). This is, therefore, a region that should not be ignored in physiotherapy practice.
Anatomy[edit | edit source]
Range of Motion[edit | edit source]
The total rotation available in the thoracic spine is 85 degrees (+/- 14.8 degrees). It contributes 80 percent of the total range of axial trunk rotation. Each thoracic segment rotates between 6 and 8 degrees. This is significantly more than the lumbar segments, which only rotate 2 to 3 degrees.
Thoracic movement is critical for optimal performance in rotational sports and the thoracic spine kinematically links the upper and lower quarters. It also contributes 55 percent of the total force during a throw.
Regions of the Thorax[edit | edit source]
- Includes: T3 to T7, true ribs 3 to 7 and sternum
- Includes: T8 to T10 and false ribs 8 to 10
- Includes: T11 and T12, floating ribs 11 and 12
NB: True ribs attach directly to the sternum via cartilage, false ribs attach to the lowest true ribs and floating ribs only have posterior attachments to the spine.
Ribs[edit | edit source]
- Ribs 1, 11 and 12 articulate with the named vertebra (i.e. rib 1 articulates with T1)
- Ribs 2 to 10 articulate with the named vertebra, as well as the body above, the intervertebral disc and the anterior surface of the transverse process of the named vertebra
- More information about the ribs is available here
The Thoracic Ring (T3-T9)[edit | edit source]
'The "thoracic ring” consists of two adjacent vertebrae and the related intervertebral disc, the right and left ribs (attached to the vertebra-disc-vertebra complex at the costovertebral joints), and the anterior attachments to the sternum/manubrium and related cartilages.'
- Zygapophyseal / facet = 2 articulations
- Costovertebral = 4 articulations
- Intervertebral = 1 articulation
- Costotransverse = 2 articulations
- Costochondral = 2 articulations
- Sternocostal = 2 articulations
Because of the strong anatomical connections between the ribs and the thoracic spine, mobilising a rib laterally will cause motion at the vertebral segments of that thoracic ring, as well as the rib on the opposite side of the body.
Thoracic Function[edit | edit source]
- Force transmission
- Central area for myofascial attachments
- Protects heart, lungs, vessels and digestive tract
- Aids optimal respiratory function
- Houses the autonomic nervous system
Thoracic Asymmetry[edit | edit source]
Regional Interdependence[edit | edit source]
The regional interdependence theory proposes that: “seemingly unrelated impairments in remote anatomical regions of the body may contribute to and be associated with a patient’s primary report of symptoms.” It has been proposed that there may also be central mechanisms involved in mediating regional interdependence.
Examples of interdependency in the thoracic spine include the following:
1. Cervical spine[edit | edit source]
- 25 percent to cervical flexion and extension
- 10 percent to cervical rotation
Thoracic spine changes are, therefore, implicated in a loss of cervical range of motion, so this area should always be assessed in patients with neck dysfunction.
Similarly, Engell and colleagues have found that when manual therapy techniques (e.g. high-velocity low-amplitude spinal manipulative therapy) are applied to the thoracic spine, forces can be transmitted to the neck.
2. Shoulder[edit | edit source]
The scapula is a sesamoid bone, which rests upon the thorax. It is influenced by the position of the thoracic spine elements and the ribs. Postures such as thoracic kyphosis, thoracic scoliosis or flattened / inverted thoracic spine, can change the resting position of the scapula.
- Thoracic kyphosis is associated with a loss of glenohumeral range of motion and impingement symptoms
- Treating the thoracic spine has been shown to alter shoulder symptoms 
3. Other Relationships[edit | edit source]
- Sympathetic nerve blocks at the thoracic spine can improve chronic upper extremity neuropathic pain
- 70 percent of patients with lateral elbow pain have co-existing thoracic pain (compared to 16 percent of the control group)
Postural and Positional Implications[edit | edit source]
Certain postural dysfunctions could result in compensatory thoracic dysfunction (i.e. ‘gives’):
- Inextensible hamstrings force the thoracic spine to 'give' into flexion during stride, lunging and long sitting
- Inextensible hip flexors can cause lordosis and kyphosis
- A leg length discrepancy and asymmetrical load can cause thoracic scoliosis
Poor cervico-thoracic postures such as:
- Muscle imbalances
- Joint incongruity
- Ligament laxity
- Altered neurodynamics
- Even minor curves cause wedging of the vertebrae and discs
- 80 percent of athletes who experience asymmetrical loading on their trunk and shoulders (e.g. javelin throwers, tennis players) have thoracic scoliosis
- It could, therefore, be proposed that scoliosis provides a mechanical advantage in asymmetrical sports
Summary[edit | edit source]
- Potentially 40 percent of patients presenting for physiotherapy with back or neck pain will have an associated thoracic spine dysfunction which needs to be assessed and managed
- Biomechanics and knowledge of the clinical anatomy of the thorax will help you to better understand the underlying pathogenesis of these conditions
- Thoracic rotation is essential for optimal sports performance and functional activities
- Postural dysfunctions such as tight hamstrings or hip flexors may force compensatory 'gives' in the thoracic spine - it is essential to look for the source of the problem
References[edit | edit source]
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