thorax, pleural cavity. bones sternum - all landmarks 12 ribs, costal cartilages - all landmarks 12...

Thorax, Pleural Cavity

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

Thoracocentesis

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.

Herpes Zoster

• Shingles

• Viral infection of Chicken pox virus

• Affect along intercostal nerve

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


Innermost intercostalis

• ORIGINInternal aspect of ribs above and below

• INSERTIONInternal aspect of ribs above and below

• ACTIONFix intercostal spaces during respiration


Subcostalis

• ORIGINInternal posterior aspects of lower six ribs

• INSERTIONInternal aspects of ribs two to three levels below

• ACTIONDepresses lower ribs


Transversus thoracis

• ORIGINLower third of inner aspect of sternum and lower three costosternal junctions

• INSERTIONSecond to sixth costal cartilages

• ACTIONDepresses upper ribs


thorax, pleural cavity. bones sternum - all landmarks 12 ribs, costal cartilages - all landmarks 12...

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