Thoracic Wall: Muscles Flashcards
What is the function of the thoracic cage?
1) protection of the upper abdominal organs
2) Site of muscle attachments
3) Resperation
What is resperation?
The change in air pressure to allow interthoracic volume to increase and thus the lungs to fill with air
What is the 2nd most important muscle of inspiration?
External Interncostal
Diaphragm is the 1st
What is the function of the external interncostal?
Elevates the ribs in insiration
What will replace the external intercostals when they reach the costochondral joint?
External intercostal membrane
What direction do the fibers of the external intercostal run?
Downward and Forward
The external intercostal takes its attachment point where?
Origin-lower boarder of ribs 1-11
Insertion- Upper boarders of ribs 2-12
What muscle will begin at the sternum and then continue as a membrane once they reach the and of the ribs?
Inner Intercostal Muscle
What is the function of the inner intercostal muscle?
Depress the ribs in forced experation
What is the fiber direction of the inner intercostal?
downward and backward
What other muscle of the thoracic cage will have fibers that run backward and downward?
Innermost intercostal
In general, what is the function of all of the intercostal muscles?
to prevent the pushing in or drawing out of the intercostal space during resperation
What muscles will depress the ribs during forces expiration?
1) Inner Intercostal
2) Innermost Intercostal
3) Subsoctalis
4) Transverus Thoracis
Which of the muscles of the thoracic wall will skip ribs to attach to another rib?
Subcostalis
The transervus thoracis takes its attachment points where?
O- posterior surface of the lower sternal body and xiphoid process
I- inner surface of costal cartilages 2-6
