Clinical examination of the thoracic spine

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Clinical examination of the thoracic spine



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Introduction


Thoracic or abdominal wall pain is a common complaint and poses a major diagnostic challenge to physician and therapist.


The pain is often referred from visceral disorders, although the frequency of musculoskeletal lesions of the thorax and the abdomen should not be underestimated. A physician not familiar with the musculoskeletal disorders of the region could be tempted to ascribe unexplained pain to vague lesions such as intercostal neuralgia, neuritis, cardiac neurosis, pleurodynia or rib syndromes. Again, lack of an exact diagnosis leads to inadequate and unsuccessful treatment. The absence of a precise (orthopaedic) diagnosis can, to a certain extent, be a consequence of the complexity of the region itself. However, another important reason is the lack of an appropriate clinical approach to this part of the body. Thorough examination should not be restricted to the routine visceral examination (e.g. auscultation, percussion and palpation) but also must include proper orthopaedic and neurological tests. Although a large number of reliable technical investigations for detecting all types of visceral disorders are available, the same cannot be said when it comes to musculoskeletal disorders, for which technical investigations are often of limited diagnostic value.


Clinically, the thoracic region is approached in a different way from the cervical or the lumbar spine because it behaves differently in many aspects.



Principal differences between the thoracic and the lumbar and cervical spines



Visceral versus musculoskeletal pain


Because referred pain from visceral problems can mimic pain of musculoskeletal origin and vice versa, the first step towards diagnosis must always be to differentiate these two categories. The character of the pain is usually of little help in the differential diagnosis because it has the same features in both. Pain referred from heart, lungs and intestines is usually poorly localized and vaguely delineated, and is referred to a segmental or multisegmental distribution. The behaviour of the pain may also mislead the examiner. One of the main characteristics of pain in lesions of moving parts is that it is brought on by posture and movement. This is also the case in thoracic lesions: if the patient’s symptoms depend on activity rather than on visceral function, a cause originating from moving parts should be considered. However, it is important to keep in mind the fact that posture, physical activity, a deep breath or a cough may also influence visceral pain in the thorax or abdomen.


The best method of differentiating is to work in two complementary ways: exclusion of any visceral disorder through a thorough internal check-up, together with positive confirmation of a provisional orthopaedic diagnosis (Fig. 25.1). This routine will also safeguard against unnecessary technical investigations and delays in diagnosis and treatment.13




Discal lesions


Discodural and discoradicular interactions are well-known causes of cervical and lumbar pain.


In a discodural lesion, a shifted component of the disc impinges on the dura and causes pain that has multisegmental characteristics (crossing the midline and occupying several dermatomes). Discodural conflicts are characterized by two sets of symptoms and signs: articular and dural (see Ch. 33).


In a discoradicular lesion, the subluxated disc component impinges on the nerve root and its dural sleeve. The pain and paraesthesia that result are strictly segmental. Discoradicular conflicts are characterized by three sets of symptoms and signs: articular, root and cord.


Disc lesions also commonly occur in the thoracic spine but often show characteristics that are quite different from those found at the lumbar and cervical spines.



• The articular signs are subtle: a discodural interaction at the cervical or lumbar level usually presents with a clear partial articular pattern: some movements hurt or are limited and others do not, always in an asymmetrical way. This is not so in the thoracic spine. Because of the rigidity of the thorax, such an obvious pattern is seldom found. Very often, only one of the six passive movements, usually a rotation, is positive and then only slightly so. Therefore diagnosis in the thoracic spine is more tentative and may have to be based on smaller, subtler abnormalities.


• Neurological deficit is seldom encountered in a thoracic disc lesion: whereas some degree of neurological deficit is a common finding in cervical or lumbar posterolateral disc lesions, muscular weakness is rarely detectable in thoracic discoradicular lesions. Also, disturbance of sensation is very rare. This absence of neurological signs is probably the outcome of the location of the nerve root in the intervertebral foramen, where it lies mainly behind the lower aspect of the vertebral body and less behind the disc (see online chapter Applied anatomy of the thorax and abdomen).


• There is no tendency to spontaneous recovery: in the lumbar and cervical spines there is usually a spontaneous cure for root pain, which seldom lasts longer than 4 months at the cervical level and 12 months at the lumbar level. At the thoracic level, no such tendency exists and constant root pain can persist for many years.


• Protrusions can usually be reduced: although thoracic disc lesions are more difficult to diagnose, they are easily and effectively cured. Protrusions – no matter how long they have been present, or whether they are posterocentral or posterolateral, or soft or hard – can usually be reduced by 1–3 sessions of manipulations. Unlike at the lumbar or cervical levels, time is not a criterion for reducibility. Hence a disc displacement may well prove reducible after constant root pain, even of several years’ standing. Traction is seldom required because the protrusions are usually of the annular type.




Referred pain


Both musculoskeletal and visceral lesions can be the source of pain referred to the thoracic and/or abdominal wall.



Pain referred from musculoskeletal structures



Dura mater and nerve roots


Pain originating from the dura mater is referred in a multisegmental way: it crosses the midline and may cover several consecutive dermatomes (see p. 18). A possible explanation for this phenomenon may lie in its multisegmental origin, which is reflected in the considerable overlap between the fibres of the consecutive sinuvertebral nerves innervating its anterior aspect.4 Recent research has demonstrated that dural pain may spread over eight segments with considerable overlap between adjacent and contralateral dura mater.5 This may be an explanation for the fact that lower cervical discodural conflicts may produce pain that spreads into the upper thoracic level (Fig. 25.2a) or that lumbar dural pain causes pain in the lower thoracic region (Fig. 25.2b).



Pain originating from a nerve root sleeve has a strict segmental reference and is restricted to the borders of the dermatome.


Thoracic disc lesions may thus cause referred pain in the thorax, not only as the result of extrasegmental reference in the case of discodural contact, but also when a discoradicular interaction has been created. However, cervical and lumbar discal lesions may also be the origin of thoracic referred pain.



Cervical disc lesions

Some cervical disc lesions may cause pain in the thoracic region.





Thoracic disc lesions

Thoracic discodural and discoradicular interactions are common causes of referred pain in the thoracic and abdominal region.




Thoracic discoradicular interactions

A posterolateral impingement on the two upper thoracic roots produces pain felt in the arm (Fig. 25.3). If the T1 nerve root is involved, pain may be referred to the ulnar side of the forearm, whereas a T2 nerve root compression gives rise to pain felt over the inner aspect of the arm from the elbow to the axilla, at the anterior aspect of the upper thorax around the clavicle and at the posterior upper thorax around the scapular spine. Clinically the upper two thoracic segments belong to the cervical spine and are thus most easily examined with the cervical segments.



If the 3rd–12th root is compressed, pain spreads unilaterally as a band around the thorax, sometimes reaching anteriorly as far as the sternum (see Fig. 25.3).


The following landmarks may be helpful in determining which root is involved:






Bones


Osseous structures usually do not give rise to much in the way of referred pain; the pain remains typically local. Intense though localized pain is a warning sign and the following conditions should be considered:




Joints and ligaments


Ligaments and joints consistently obey the rules of referred pain, which means that the deeper the location of the affected structure and the closer its position to the midline, the more referred pain is to be expected. On the other hand, the further the lesion lies from the spinal axis and the more superficial it is, the more accurate will be its localization by the pain it provokes.



• Manubriosternal and sternoclavicular joints: as these are superficially located, the pain is felt locally.


• Costochondral and chondrosternal joints (Tietze’s syndrome and costochondritis): the patient is able to indicate the site of the lesion accurately.


• Intervertebral facet joints: these give rise to unilateral paravertebral pain, felt deeply and locally, but not going further lateral than the medial edge of the scapula. If several joints are affected at the same time, as may be the case in ankylosing spondylitis, the pain spreads more in a craniocaudal direction than mediolaterally; the opposite is true for a disc protrusion.


• Costovertebral and costotransverse joints: the pain is felt unilaterally between the vertebral column and the scapula.


• Anterior longitudinal ligament: when this ligament is affected, pain is usually located anteriorly behind the sternum.


• Posterior longitudinal ligament: involvement of this ligament causes pain in the back, felt centrally between the scapulae.


• Disorders of the costocoracoid fascia or the trapezoid and conoid ligaments (see online chapter Disorders of the inert structures): the pain is usually felt in the infraclavicular fossa.




Pain referred from visceral structures














Reproductive system


Disorders of the ovaries (T11–L1) may result in unilateral low abdominal pain, sometimes felt in the periumbilical area. Testicular problems (T11–L1) give rise to scrotal pain, sometimes radiating into the groin and to the side.


See Box 25.1 for a summary of referred pain in the thorax and abdomen.


Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on Clinical examination of the thoracic spine
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