thorax, pleural cavity. bones sternum - all landmarks 12 ribs, costal cartilages - all landmarks 12...
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Bones
• sternum - all landmarks
• 12 ribs, costal cartilages - all landmarks
• 12 thoracic vertebrae - all landmarks
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
Diaphragm
• muscle + fibrous connective tissue - separates thoracic & abdominal cavities
• domed in center
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
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
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
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
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 arteriesterminate 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.
Blood Vessels
• internal thoracic artery (branch of subclavian): divides behind #6 costal cartilage: – a. superior epigastric artery – b. musculophrenic artery
Nerves
• Intercostal nerves = ventral rami of thoracic nerves 1-11 – to intercostal muscle, skin– travel in costal grooves, between internal &
innermost intercostal muscle.
Muscles
• External intercostalis
• Internal intercostalis
• Innermost intercostalis
• Subcostalis
• Transversus thoracis
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
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
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
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
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