module 1 Flashcards
(294 cards)
what is the diaphragm
thin musculotendinous septum
septum
a wall or partition dividing a body space or cavity each named according to its location
what does the diaphragm separates
the thoracic and abdominal cavities
what is the principle muscle of respiration
diaphragm
what does the diaphragm do during respiration
when it contracts its domes flatten to increase the volume of the thoracic cavity during inspiration
features of the diaphragm
- right dome
- left dome
- central tendon
- right crus
- left crus
right dome
can rise to the level of the upper border of the 5th rib
left dome
can rise to the lower border of the 5th rib
central tendon
peripheral muscular fibers of the diaphragm attach to the inferior margin of the thoracic cage and the lumbar vertebrae, to converge on the central tendon
location of central tendon
inferior to the fibrous pericardium of the heart
right crus
muscular extension of the diaphragm that originates from the anterolateral surface of the upper three lumbar vertebrae
left crus
muscle extension of the diaphragm that originates from the anterolateral surface of the upper 2 lumbar vertebrae
apertures of the diaphragm
- caval opening
- esophageal hiatus
- aortic hiatus
caval opening
in the central tendon
- level of the 8th thoracic vertebra (T8)
what is the caval opening an opening for
the inferior vena cava (IVC)
where is the IVC situated
in the posterior thorax on the right side
esophageal hiatus
- in the right crus at T10
- opening for the esophagus
- as the esophagus descends through the thorax it deviates to the left, lying anterior to the thoracic
aortic hiatus
- between the right and left crus
- anterior to T12
what is the aortic hiatus an opening for ?
the abdominal portion of the aorta
where is the aortic hiatus located
on the left side of the posterior thorax
what are the intercostal muscle
- external, internal , innermost
- seriers of muscles runnning between adjacent ribs forming the chest wall
where are the external and internal located
inbetween ribs
what do the innermost intercostals form
an incomplete layer that can span across 2-3 ribs
external intercostals
- fibers run anterinferiorly from the lower border of the ribe