Clinical Reasoning and Pathologies of the Thoracic Spine

Original Editor - Jess Bell based on the course by Tanya Bell-Jenje
Top Contributors - Jess Bell, Carin Hunter and Rucha Gadgil

Introduction[edit | edit source]

The thoracic spine is a complex area that has been largely overlooked in research.[1] While only 13 percent of individuals specifically report thoracic pain each year,[2] it is now recognised that the thorax can be a silent contributor to other distal and proximal conditions.[1] Moreover, a number of non-mechanical pathologies can masquerade as musculoskeletal thoracic pain. All of these conditions must be considered when assessing patients who have thoracic pain.

Muscles of the Thorax[edit | edit source]

There are 112 muscle attachments in the thorax. This page looks at some of the muscles that can affect the thorax. Additional information on thoracic spine musculature is available here.

Intercostals[edit | edit source]

There are 11 pairs of intercostal muscles. Each muscle has three layers arranged from superficial to deep:[3]

  • External
  • Internal
  • Innermost

The intercostal nerves mostly come from the anterior rami of the T1 to T11 spinal nerves.[3] Along with the intercostal artery and vein, these nerves run between the intermediate and deep layers of the intercostal muscles. The T7 to T11 intercostal nerves leave the thoracic wall and enter the abdominal wall to innervate the abdominal peritoneum.[4] They supply the:[4]

  • Ribs and costal cartilages
  • Intercostal muscles (all layers)
  • Parietal pleura, which lines the inner surface of the thoracic cavity, including the diaphragm, pericardium and thoracic aorta

Because of this shared innervation, diseases of the thoracic wall or cavity may masquerade as dermatomal pain arising from the thoracic spine.[4] Thus, it is essential to constantly assess a patient for red flags. If a patient has a poor response to treatment, this can indicate a more serious pathology and is considered a key red flag.[4][5]

Iliocostalis[edit | edit source]

Iliocostalis is the most lateral of the erector spinae muscles. It is divided into three parts:[6]

  • Iliocostalis cervicis
  • Iliocostalis thoracis
  • Iliocostalis lumborum

Iliocostalis lumborum originates at the iliac crest and inserts into the L1 to L4 lumbar transverse processes, the angle of ribs 4 to 12, and the thoracolumbar fascia. Iliocostalis cervicis and thoracis have attachments as high as the upper 6 ribs and the transverse processes of C4.[6] Iliocostalis, therefore, links lumbo-pelvic dysfunction with thoracic dysfunction. Hypertonicity in this muscle can potentially have an impact on the thoracic rings.[4]

Pectoralis Major[edit | edit source]

Pectoralis major makes up the bulk of the chest muscles. It is a thick, fan-shaped muscle that originates at the:[7]

  • Anterior sternum (down to the xiphoid process)
  • Clavicle
  • 6th rib (sternal end)
  • Upper 6 costal cartilages
  • Aponeurosis of the external oblique

It inserts into the lateral lip of the bicipital groove on the humerus.[7]It also has fascial links with latissimus dorsi.[4][8]

Overactivity of pectoralis major is associated with thoracic kyphosis and anterior translation of the humerus.[4] Horizontal clavicles are a clinical sign of overactivity in this muscle.[4] Pectoralis stretching can help to reduce kyphosis, as well as forward head position / rounded shoulder position.[9][10]

Figure 1. Exercise to reduce thoracic kyphosis.

The exercise shown in Figure 1 can be used to improve thoracic and scapula motor control. It can also reduce thoracic kyphosis by increasing the activity of the middle and lower fibres of trapezius and reducing overactivity in the upper fibres of trapezius.[4]

NB: it is important to improve activation of lower trapezius in patients who have an increased thoracic kyphosis. The cue “down and out” should be given during exercises, rather than “down and in”.[4]

Rhomboid Major and Minor[edit | edit source]

The rhomboids consist of two muscles:[11]

  • Rhomboid major
    • A quadrangular muscle
    • Inferior to rhomboid minor
    • Originates at the T1 to T4 spinous processes
    • Inserts into the medial margin of the scapula below the root of the inferior angle[4]
  • Rhomboid minor
    • A cylindrical muscle
    • Originates at the ligamentum nuchae and C7 and T1 vertebra
    • Inserts into the medial margin at the root of the spine of the scapula

Overactivity in these muscles leads to:[4]

  • Inverted thoracic spine with compression forces on the facets
  • Downward rotation of the scapula, which loads the cervical spine
  • Dural irritation

Serratus Anterior[edit | edit source]

Serratus anterior is a fan-shaped muscle. It lies deep to the scapula and pectoral muscles:[12]

  • It originates on the superolateral surfaces of the upper 8 or 9 ribs
  • It runs backwards and inserts along the superior angle, medial border, and inferior angle of the scapula

This muscle is a powerful protractor (abductor). It is also involved in upward rotation (which allows for overhead activity), posterior tilt and external rotation of the scapula. It holds the scapula flat against the rib cage and can mobilise the thoracic spine into kyphosis.[4][12] 

Figure 2. Hug an aunt stretches for serratus anterior.

The exercises shown in Figure 2 are useful for:[4]

  • Inverted thoracic spine
  • Possible dural pain
  • Targeting the various digitations of serratus anterior

External Oblique vs Serratus Anterior[edit | edit source]

External oblique, internal oblique and transversus abdominis are the three anterolateral abdominal wall muscles. The external oblique is the largest, thickest and most superficial of these muscles:[4][13]

  • It attaches to the lower 6 or 7 ribs (and, therefore, can affect the activity of the diaphragm)[4]
  • It runs obliquely from superior-lateral to inferior-medial
  • It inserts on the iliac crest

The external oblique and serratus anterior interdigitate from the 5th to the 9th ribs.[4] The opposing action of these muscles (e.g. during rowing or coughing) creates a stress reaction, which is a major contributor to stress fractures.[14]

The Diaphragm[edit | edit source]

The diaphragm is a dome-shaped muscle of respiration that is innervated by the phrenic nerve (C3-5). The superior portion of the diaphragm originates at the:[15]

  • Xiphoid process anteriorly
  • The lower 6 costal cartilages of the thorax laterally via digitations that cross those of transversus abdominis[16]
  • The first two lumbar vertebrae posteriorly

It converges into a central tendon which forms the dome’s crest. The peripheral segment attaches to the chest wall and abdominal cavity.[15]

The diaphragm is connected via fascia to the:[4]

  • Aortic system
  • Inferior vena cava
  • Liver
  • Psoas muscles
  • Quadratus lumborum
  • Transversus abdominis
  • Pelvic floor
  • Cardiac system (pleura and pericardium)
  • Deep and median neck fascia
  • Occiput
  • Dura
  • Phrenic-oesophageal ligaments
  • Kidneys

The diaphragm and intercostals are the only muscles that are active during quiet inspiration.[17] During quiet exhalation, the diaphragm, rib cage and chest wall relax and return to their original position, which expels the air from the lungs.[15]

The diaphragm is, therefore, essential for optimal respiratory physiology. It also affects many other systems as well, including the nervous system, muscle and postural systems, as well as the lymphatic system.[4][17]

The Effect of Diaphragmatic Bracing on the Thoracic Spine[edit | edit source]

Diaphragmatic bracing in low load situations can occur in:[4]

  • Chronic low back pain[18]
  • PTSD
  • Panic attacks
  • COVID-19
Figure 3. 90/90 bridge with ball and balloon exercise.

Patients who engage this bracing strategy may present with back, thoracic, neck and rib pain. Bracing fixes the thoracic wall and reduces thoracic mobility. It can lead to:[4]

  • Hypocapnia (i.e. decrease in carbon dioxide levels)
  • Increased respiratory rate
  • Apical breathing
  • Irregular respiratory rate

Normally, ribs 1 to 7 posteriorly rotate during full inspiration and anteriorly rotate during full expiration.[19][20] It is important to teach patients correct respiration as optimal breathing mechanics promote synchronous movement of the ribs.

The 90/90 bridge with ball and balloon exercise (see Figure 3) was created to enhance function and breathing, improve posture and stability and to reduce pain.[21]

Pathologies[edit | edit source]

Spinal Masqueraders[edit | edit source]

In some instances, thoracic pain may have non-mechanical origins. Visceral or systemic conditions that present as thoracic pain are known as spinal masqueraders. Examples of thoracic spinal masqueraders include:[4]

Thoracic Outlet Syndrome[edit | edit source]

Thoracic outlet syndrome (TOS) is a group of disorders that cause compression of the nerves, arteries or veins as they exit the thoracic outlet. TOS typically occurs in three places:[4]

  • Scalene triangle
  • Costoclavicular space
  • Retropectoral space

Postural / thoracic kyphosis, tight bra straps, overactive subclavius, and the presence of a cervical rib can narrow the costoclavicular space and create neurovascular symptoms.[4] Structures usually affected in TOS are the:[22]

  • Subclavian artery and vein
  • Axillary artery and vein
  • Brachial plexus

There are three types of TOS:[22][23]

  1. Neurogenic (i.e. brachial plexus)
    • Most common type (approximately 95 percent of cases[24])
    • Symptoms include:
      • Pain
      • Weakness
      • Heaviness in the arm
      • Paraesthesia
    • Neurogenic symptoms tend to be worse with overhead activities or when the patient's arm is dangling at his / her side
  2. Venous (i.e. subclavian vein) - also known as Paget–von Schroetter syndrome[24]
    • Symptoms include:
      • Swelling
      • Pain
      • Bluish discolouration
  3. Arterial (i.e. subclavian artery)
    • Least common type
    • Symptoms include:
      • Pain
      • Coldness
      • Paleness in the arm

TOS is often missed by clinicians - the average time to diagnosis is 60 months. TOS may be mistaken for carpal tunnel, cervical nerve root compression, psychosocial issues, complex regional pain syndrome, fibromyalgia, MS etc.[4]

TOS can be diagnosed using the following tests and investigations:[25]

  • Adson’s test
  • Elevated arm stress test (Roos test)
    • It has been found that using the Adson and Roos tests as a cluster results in higher specificity than using these tests on their own[24]
  • Upper limb tension test
  • Nerve conduction study (0ften negative)
  • MRI in elevation
  • Doppler / duplex ultrasound
  • Scalene blocks can be used as a diagnostic tool[23]
  • Warm and cold thermal detection also has good reliability[26]

Stress Fracture of the Ribs[edit | edit source]

Stress fractures of the ribs are typically associated with sports that have:[4]

  • High strain magnitudes (e.g. weightlifting)
  • High load repetitions (e.g. golf, rowing, throwing, over-training)

They tend to occur when the opposing actions of serratus anterior and external oblique generate pulling forces and, consequently, a stress reaction (see above).[14]

Rowing:

  • The incidence of rib stress fractures in rowing is between 6 and 12 percent:[27]
    • Occurs most often in ribs 5 to 9
    • Typically antero-lateral, but can be postero-lateral[14]

Golf:[28]

  • Most commonly occurs on the lead-side (i.e. non-dominant side) and affects the postero-lateral ribs
  • Ribs 4 to 6 are most often affected

Rib stress fractures are diagnosed based on history and bone scans, CT or MRI.[4] Patients usually require 3 to 9 weeks off sports.[4][29][30] Patients tend to present with:[29]

  • History of insidious onset (overload) with sudden pain
  • Pain with deep breathing, coughing, sneezing, turning in bed
  • Inability to sleep on the affected side
  • Severe, specific, palpable pain on examination
  • Positive rib spring
  • Altered breathing mechanics
  • Pain with push-up and with resisted serratus anterior testing
  • Pain with sit-up, including with an oblique bias

Manubriosternal Joint Pain[edit | edit source]

Manubriosternal joint pain often occurs as a result of an acceleration / deceleration injury[31] (e.g. throwing, serving). Sclerosis of this joint is also seen in various types of arthritis, including:[4]

Costochondritis[edit | edit source]

Costochondritis is inflammation of the costochondral or chondrosternal joints. It is more common in adults aged over 40 years. In 90 percent of patients, more than one rib is affected. The ribs most frequently affected are ribs 2 to 5.[32]

  • Mild to severe localised pain, but may refer to the shoulder, neck and arms[4]
  • It is important to rule out seronegative arthritis, pneumonia, cardiovascular and malignant disorders[4]
  • It is treated with NSAIDs and it can take weeks or months to resolve[32]

Costochondritis can be mistaken for Tietze syndrome, but this condition is characterised by swelling of a single costal cartilage. Ribs 2 or 3 are usually affected and it is more common in younger patients.[32]

Cervical Facet Pain[edit | edit source]

It is well established that cervical discs, as well as cervical facet joints refer pain to the upper thorax.[4]

Thoracic Disc Pathology[edit | edit source]

Thoracic disc pathology is rare and individuals are often asymptomatic. One of the reasons it is so rare is due to the thickness of the thoracic disc - it is thinner than in other regions. The ratio of the thoracic disc to the vertebral body is 1:5 (vs 2:5 in the cervical spine and 1:3 in the lumbar spine).[4]

Figure 4. Spinal dermatomes.

In 75 percent of cases, thoracic disc pathology occurs at T8 or below, peaking around T11 or T12.[33] Only 1 percent of prolapses with severe myelopathy occur in the thoracic spine.[4]

There are two types of disc pathology:[4]

  • Central thoracic pain (myelopathic):
    • Leg paralysis and spinal cord compression
    • Bladder and bowel impairment
  • Dermatomal unilateral pain (radicular)
    • Compression of the nerve root[4]
    • Pain follows the intercostal dermatomal route (see Figure 4)

Summary[edit | edit source]

  • It is beneficial to restore a neutral thoracic spine
  • Serratus anterior is key to restoring an optimal thoracic kyphosis from a dysfunctional inverted position
  • Teaching correct respiration is important as good breathing mechanics prompt synchronous movement of the ribs
  • As there are many thoracic spinal masqueraders, red flags should be constantly assessed:
    • A key red flag to consider is a poor response to treatment

References[edit | edit source]

  1. 1.0 1.1 Bell-Jenje T. The Thorax Simplified - Anatomy, Biomechanics and Regional Interdependence Course. Physioplus, 2021.
  2. Leboeuf-Yde C, Nielsen J, Kyvik KO, Fejer R, Hartvigsen J. Pain in the lumbar, thoracic or cervical regions: do age and gender matter? A population-based study of 34,902 Danish twins 20–71 years of age. BMC Musculoskelet Disord. 2009;10(39).
  3. 3.0 3.1 Tang A, Bordoni B. Anatomy, Thorax, Muscles. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538321/
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.27 4.28 4.29 4.30 4.31 4.32 4.33 4.34 4.35 Bell-Jenje T. Assessment and Treatment of the Thoracic Spine Course. Physioplus, 2021.
  5. Finucane LM, Downie A, Mercer C, Greenhalgh SM, Boissonnault WG, Pool-Goudzwaard AL et al. International framework for red flags for potential serious spinal pathologies. J Orthop Sports Phys Ther. 2020;50(7):350-72.
  6. 6.0 6.1 Henson B, Kadiyala B, Edens MA. Anatomy, Back, Muscles. [Updated 2021 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537074/
  7. 7.0 7.1 Solari F, Burns B. Anatomy, Thorax, Pectoralis Major Major. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525991/
  8. Pandya R. Upper Extremity Myofascial Chains Course. Physioplus, 2021.
  9. Roddey TS, Olson SL, Grant SE. The effect of pectoralis muscle stretching on the resting position of the scapula in persons with varying degrees of forward head/rounded shoulder posture, Journal of Manual & Manipulative Therapy. 2002;10(3):124-8.
  10. Kim MK, Lee JC, Yoo KT. The effects of shoulder stabilization exercises and pectoralis minor stretching on balance and maximal shoulder muscle strength of healthy young adults with round shoulder posture. J Phys Ther Sci. 2018;30(3):373-80.
  11. Farrell C, Kiel J. Anatomy, Back, Rhomboid Muscles. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534856/
  12. 12.0 12.1 Lung K, St Lucia K, Lui F. Anatomy, Thorax, Serratus Anterior Muscles. [Updated 2020 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK531457/
  13. Seeras K, Qasawa RN, Ju R, et al. Anatomy, Abdomen and Pelvis, Anterolateral Abdominal Wall. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525975/
  14. 14.0 14.1 14.2 Karlson KA. Rib stress fractures in elite rowers. A case series and proposed mechanism. Am J Sports Med. 1998;26(4):516-9.
  15. 15.0 15.1 15.2 Bains KNS, Kashyap S, Lappin SL. Anatomy, Thorax, Diaphragm. [Updated 2020 Apr 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519558/
  16. Bordoni B, Zanier E. Anatomic connections of the diaphragm: influence of respiration on the body system. J Multidiscip Healthc. 2013 Jul 25;6:281-91. doi: 10.2147/JMDH.S45443. PMID: 23940419; PMCID: PMC3731110. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3731110/
  17. 17.0 17.1 Clifton-Smith T. How We Breathe Course. Physioplus, 2020.
  18. Kolar P, Sulc J, Kyncl M, Sanda J, Cakrt O, Andel R, Kumagai K, Kobesova A. Postural function of the diaphragm in persons with and without chronic low back pain. J Orthop Sports Phys Ther. 2012 Apr;42(4):352-62. doi: 10.2519/jospt.2012.3830. Epub 2011 Dec 21. PMID: 22236541. https://www.jospt.org/doi/full/10.2519/jospt.2012.3830
  19. Beyer B, Sholukha V, Dugailly PM, Rooze M, Moiseev F, Feipel V et al. In vivo thorax 3D modelling from costovertebral joint complex kinematics. Clin Biomech (Bristol, Avon). 2014;29(4):434-8.
  20. Lee DG. Biomechanics of the thorax - research evidence and clinical expertise. J Man Manip Ther. 2015;23(3):128-38.
  21. Boyle KL, Olinick J, Lewis C. The value of blowing up a balloon. N Am J Sports Phys Ther. 2010;5(3):179-88.
  22. 22.0 22.1 Li N, Dierks G, Vervaeke HE, Jumonville A, Kaye AD, Myrcik D et al. Thoracic outlet syndrome: a narrative review. J Clin Med. 2021;10(5):962.
  23. 23.0 23.1 Illig KA, Donahue D, Duncan A, Freischlag J, Gelabert H, Johansen K et al. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. J Vasc Surg. 2016;64(3):e23-35.
  24. 24.0 24.1 24.2 Jones MR, Prabhakar A, Viswanath O, Urits I, Green JB, Kendrick JB et al. Thoracic outlet syndrome: a comprehensive review of pathophysiology, diagnosis, and treatment. Pain Ther. 2019;8(1):5-18.
  25. Povlsen S, Povlsen B. Diagnosing thoracic outlet syndrome: current approaches and future directions. Diagnostics (Basel). 2018;8(1):21.
  26. Ridehalgh C, Sandy-Hindmarch OP, Schmid AB. Validity of clinical small-fiber sensory testing to detect small-nerve fiber degeneration. J Orthop Sports Phys Ther. 2018;48(10):767-74.
  27. Warden SJ, Gutschlag FR, Wajswelner H, Crossley KM. Aetiology of rib stress fractures in rowers. Sports Med. 2002;32(13):819-36.
  28. Lee AD. Golf-related stress fractures: a structured review of the literature. J Can Chiropr Assoc. 2009;53(4):290-99.
  29. 29.0 29.1 Evans G, Redgrave A. Great Britain Rowing Team guideline for diagnosis and management of rib stress injury: part 2 - the guideline itself. Br J Sports Med. 2016;50(5):270-2.
  30. McDonnell LK, Hume PA, Nolte V. Rib stress fractures among rowers: definition, epidemiology, mechanisms, risk factors and effectiveness of injury prevention strategies. Sports Med. 2011;41(11):883-901.
  31. Bar-Haim R, Shtarker H, Biswas S, Waksman I, Altman E. Case report: surgical management of painful manubriosternal pseudoarthrosis. Front Surg. 2021;8:640089.
  32. 32.0 32.1 32.2 Proulx AM, Zryd TW. Costochondritis: diagnosis and treatment. Am Fam Physician. 2009;80(6):617-20.
  33. Fogwe DT, Petrone B, Mesfin FB. Thoracic Discogenic Syndrome. [Updated 2020 Nov 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470388/