MRCS Part B (OSCE) - Online Resources

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The functions of the bony thorax are to:

• Protect the contents of the upper abdomen and chest.
• Provide attachments to the upper limb, chest and core muscles.
• Provide attachment to the mammary glands.
• Provide attachment to the intercostal muscles

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The thoracic skeleton:

• 12 pairs of ribs and costal cartilages.
• 12 thoracic vertebrae and intervertebral discs.
• Ribs 1-7 :  True ribs (attach directly to sternum with their own                          costal cartilage).
• Ribs 8-10 : False ribs (attach to the costal cartilages above them).
• Ribs 11-12 :  Floating.
• Sternal angle                  :  Corresponds to lower border of T4 vertebra.
• Body of sternum :  Extends between T5-T9 vertebra.
• Xiphoid process : At level of T10 vertebra.

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• Posteriorly :     T1 vertebra.
• Laterally :     Both 1^st ribs.
• Anteriorly :     Costal cartilages and the superior border of the                                                                     manubrium.

Note:  The superior thoracic aperture is synonymous with the thoracic inlet/outlet.

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The following structures pass thought the superior thoracic aperture:

• Trachea.
• Oesophagus.
• Thoracic duct.

Note: The apex of the lung is a content of the superior thoracic aperture.

 

Nerves:

• Phrenic nerves.
• Recurrent laryngeal nerves.
• Right and left vagus nerves.
• Sympathetic trunks.

   

  Arteries:

  • Common carotid arteries (left and right).
  • Subclavian arteries (left and right).
  • Brachiocephalic trunk

   

  Veins:

  • Internal jugular veins.
  • Brachiocephalic veins.
  • Subclavian veins.

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The causes of thyroid lumps can be subdivided into:

 Benign

• Thryoid cyst
• Thryoid adenomas
• Hyperplastic nodules
• Multinodular goitre

 Inflammatory/Autoimmune

• Hashimoto’s disease
• Grave’s disease
• Riedel’s disease

 Malignant

• Papillary carcinoma
• Follicular carcinoma
• Medullary carcinoma
• Anaplastic carcinoma
• Lymphoma

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"Once the right vagus nerve has given rise to the right recurrent laryngeal nerve, it continues inferiorly through the superior mediastinum to the right of the trachea, behind the right brachiocephalic vein, superior vena cava and hilum of the lung. Here it contributes to the pulmonary plexus. The right vagus nerve also provides the oesophageal nerve plexus and cardiac plexus. "

"The ligamentum arteriosum is the remnant of the ductus arteriosus connecting the pulmonary artery and the descending aortic arch in foetal life. Later in life, it persists as a fibrous structure between the left pulmonary artery and the aortic arch. "

"Thoracic outlet syndrome describes compression of the subclavian vessels or branches of the brachial plexus as they pass from the thorax into the arm. "

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The signs and symptoms of thoracic outlet syndrome can be classified as:

• Arterial :    Upper limb ischaemia, emboli.
• Venous :    Upper limb pain, swelling.
• Neurological :    Pain, paraesthesia, weakness, muscle wasting.

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Causes of thoracic outlet syndrome include:

• Cervical rib.
• Fibrous band.
• Neck trauma such as whiplash injury.
• Mailgnancy.
• Callus from an old clavicular fracture.
• Abnormal muscular insertions/hypertrophy.

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