Muscles Of Thoracic Wall

Question 1

external intercostal attachments, action and innervation

Answer 1

attachments: inferior border of rib above, superior border of rib below
action: elevates ribs during inspiration
innervation: intercostal nerves

Question 2

internal intercostal attachments, action and innervation

Answer 2

attachments: inferior border of rib above, superior border of rib below
action: depresses ribs during expiration
innervation: intercostal nerves

Question 3

innermost intercostal attachments, action and innervation

Answer 3

attachments: inferior border of rib above, superior border of rib below
action: aids in expiration
innervation: intercostal nerves

Question 4

thoracic diaphragm attachments, action, and innervation

Answer 4

attachments: xiphoid process, costal cartilages of lower ribs 7-12, lumbar vertebrae
action: primary muscle of respiration
innervation: phrenic nerve