Muscles of expiration Flashcards
What are the principal muscles that produce expiration?
Internal intercostals
Muscles of abdominal wall
Where do the internal intercostal muscles lie?
Beneath the external ones
Where do the fibres of the intercostal muscles run?
Run forward, from below, upward
Where do the internal intercostal muscles run from?
From the angles of the ribs behind, to the intercostal spaces in front.
What happens when force is applied in the direction of the internal intercostal fibres?
As force is applied, ribs move downwards.
The ends of the ribs, with the sternum move backwards.
Action of the internal intercostals move the anterior chest wall downwards and backwards.
What effects do the muscles of the abdominal wall have on expiration?
Raise the intra-abdominal pressure - pushes the diaphragm up.
Abdominal wall muscles pull the lower ribs downwards, assisting the action of the internal intercostals.
Where do the rectus abdominis muscles go from?
5,6,7th ribs down to the pubis.
What is the transverse abdominis?
Innermost of the three sheets of muscles.
Fibres run horizontally, the uppermost one of from the lowest four ribs, to insert of the sheet of tendon which goes to the midline.
What is the outside transversus?
Internal oblique.
Fibres arise form the iliac crest and fan out in many directions, the highest one inserting on the lowest 3 ribs.
What is outside the internal oblique?
External oblique
Arises from the lower 7 ribs, and inserts partly on the iliac crest, partly into this broad tendinous sheet, the external oblique aponeurosis.
