Thoracic Cage and mechanics of breathing

• Chest drain

  • 5th intercostal space
  • find angle of Louis (2nd rib) then count down
• Count vertebra down from C7 (bump in back of neck)
• Articular facet - articulates with the vertebra above and the corresponding numbered vertebra
• Tubercle - articulates with numerically corresponding vertebra
• costal groove - for intercostal vein, artery and nerve
• 1st rib

  • thick and flat in horizontal plane
  • only 1 articular facet (with 1st vertebra)
  • 2 tubercles - vertebral and anterior scalene muscle
  • grooves for subclavian vessels
  • no costal groove
• 11th and 12th ribs

  • only 1 articular facet
  • no costal cartilage (floating)
  • 2nd and 10th ribs also sometimes known as atypical due to 1 articular facet
• True ribs: attach directly to sternum (1st to 7th)

  False ribs: attach onto another rib (8th to 10th)

  Floating ribs: don’t attach to anything (11th and 12th)
• Chest drain - insert the needle between the ribs, or just above lower rib.
• Thoracic outlet syndrome

  • compression of
  • brachial plexus
  • neurological symptoms
  • reduced sensation
  • often ulnar nerve
  • subclavian vessels
  • arterial symptoms
  • ischaemia, claudication
  • venous symptoms
  • DVT, swelling
• Causes of thoracic outlet syndrome

  • cervical rib
  • bony abnormalities
  • e.g. post-fracture callus on 1st rib/clavicle
  • fibrous bands
  • e.g. costoclavicular ligament
  • muscular hypertrophy/inflammation
  • often scalene muscles
• Subclavian steal syndrome

  • proximal stenosis of subclavian artery causes claudication
  • blood bypasses stenosis using cerebral collaterals
  • carotids and contralateral vertebral artery are pre-stenosis
  • ipsilateral vertebral artery is post-stenosis
  • use of arm steals blood from brain causing syncope