Thorax, Pleural Cavity

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Thorax, Pleural Cavity
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Bones

• sternum - all landmarks
• 12 ribs, costal cartilages - all landmarks
• 12 thoracic vertebrae - all landmarks

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Borders

• 1. superior thoracic aperture ( thoracic inlet) -
  opening to neck,
• superior borders of manubrium, 1st pair ribs,
  costal cartilages, 1st thoracic vertebrae
• 2. inferior thoracic aperture / thoracic outlet -
  opening to abdomen
• inferior borders of T12 vertebra ribs 12, 11
  costal cartilages 10, 9, 8, 7, xiphoid

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Diaphragm

• muscle fibrous connective tissue - separates
  thoracic abdominal cavities
• domed in center

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Pleural sacs

• a continuous serous membrane folded back on
  itself to form a double layer
• 1. visceral pleura - inner layer - forms external
  surface covering of lung 
• 2. parietal pleura - outer layer - forms inner
  lining of thoracic wall 
• 3. both layers meet at root

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Pleural sacs

• Pleural cavities potential space - contains thin
  serous fluid layer, slight negative pressure
• Regions of parietal pleura are named by
  surrounding structures
• cervical/apical, costal, diaphragmatic,
  mediastinal
• Recesses narrow clefts at edges of pleura, where
  lungs don't extend
• costodiaphragmatic - most inferior, between
  costal peripheral border of diaphragm, first
  place to find fluid accumulation in X-ray
• costomediastinal - most anterior, medial, in
  front of mediastinum

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Thoracocentesis
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Mediastinum

• central structures between two pleural sacs,
  sternum vertebral bodies
• Heart pericardium, chambers, blood supply,
  pulmonary vessels, ligamentum arteriosumvagus
  nerve, recurrent laryngeal nerve
• Trachea
• Esophagus
• Phrenic nerve in mediastinal pleura -- to
  pericardium

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Blood Vessels

• Intercostal arteries - anterior posterior,
  subcostal (12th)
• 1st and 2nd posterior intercostal artery - branch
  off supreme (superior) intercostal artery, which
  branches off costocervical trunk of subclavian
  artery
• 3d - 11th posterior intercostal, subcostal
  artery - are branches of thoracic aorta

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Blood Vessels

• 1st- 5th (or 6th) anterior intercostal artery
  branches of internal thoracic artery
• 6th (or 7th) - 9th anterior intercostal arteries
  - are branches of musculophrenic artery -
  anterior posterior intercostal
  arteries terminate by anastomosing with each
  other
• There are no anterior intercostal arteries in the
  most inferior two intercostal spaces. These areas
  are provided by posterior intecostal arteries
  only.

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Blood Vessels

• internal thoracic artery (branch of subclavian)
  divides behind 6 costal cartilage
• a. superior epigastric artery
• b. musculophrenic artery

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Nerves

• Intercostal nerves ventral rami of thoracic
  nerves 1-11
• to intercostal muscle, skin
• travel in costal grooves, between internal
  innermost intercostal muscle.

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Herpes Zoster

• Shingles
• Viral infection of Chicken pox virus
• Affect along intercostal nerve

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Muscles

• External intercostalis
• Internal intercostalis
• Innermost intercostalis
• Subcostalis
• Transversus thoracis

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External intercostalis

• ORIGINInferior border of ribs as far back as
  posterior angles
• INSERTIONSuperior border of ribs below, passing
  obliquely downwards and backward
• ACTIONFix intercostal spaces during respiration.
  Aids forced inspiration by elevating ribs
• NERVEMuscular collateral branches of intercostal
  nerves

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Internal intercostalis

• ORIGINInferior border of ribs as far back as
  posterior angles
• INSERTIONSuperior border of ribs below , passing
  obliquely downwards and backwards
• ACTIONFix intercostal spaces during espiration.
  Aids forced inspiration by elevating ribs
• NERVEMuscular collateral branches of intercostal
  nerves

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Innermost intercostalis

• ORIGINInternal aspect of ribs above and below
• INSERTIONInternal aspect of ribs above and below
• ACTIONFix intercostal spaces during respiration
• NERVEMuscular collateral branches of intercostal
  nerves

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Subcostalis

• ORIGINInternal posterior aspects of lower six
  ribs
• INSERTIONInternal aspects of ribs two to three
  levels below
• ACTIONDepresses lower ribs
• NERVEMuscular collateral branches of intercostal
  nerves

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Transversus thoracis

• ORIGINLower third of inner aspect of sternum and
  lower three costosternal junctions
• INSERTIONSecond to sixth costal cartilages
• ACTIONDepresses upper ribs
• NERVEMuscular collateral branches of intercostal
  nerves

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