Thorax Flashcards
(14 cards)
What are the three types of ribs
True (1-7)
False (8-10)
Floating (11-12)
Explain the parts of a typical rib (3-9)
Head Neck Tubercle Body Costal grove
Describe the first rib
Broad
Shortest
Most sharply curved
Contributes to the roof more then the wall of the thoracic cavity
Two groves that are separated by the scalene tubercle
Describe the 10-12 ribs
Only have facets on their heads
11 and 12 are short and have no necks or tubercles
What are characteristic features of thoracic vertebrae
Bilateral superior and inferior costal facets (demifacets) on their body’s for articulating with the heads of ribs
Costal facets on the transverse process for articulating with the tubercles of ribs
Long inferiority slanting spinous processes that overlap the IV disc and vertebra
Muscles of the thoracic wall
External intercostal Internal intercostal Innermost intercostal Transverse thoracis Subcostal Levatores costarum Serratus posterior superior Serratus posterior inferior
External intercostal
Superior = inferior border of ribs
Inferior = superior border of ribs below
Innervation = intercostal nerve
Main action = during forced inspiration elevate ribs
Internal intercostal
Superior - inferior border of ribs
Inferior - superior border of ribs below
Innervation - intercostal nerve
Main action - during forced respiration interosseus part depresses ribs interchondral part elevates ribs
Transversus thoracis
Superior - posterior surface of lower sternum
Inferior - internal surface of costal cartilages 2-6
Innervation - intercostal nerve
Main action - weakly depresses ribs
Subcostal
Superior - internal surface of lower ribs near their angles
Inferior - superior borders of 2 or 3 ribs below
Innervation - intercostal nerve
Main action - act in some manner as internal intercostal muscles
Levatores costarum
Superior - transverse process of c7-t11
Inferior - subjacent ribs between tubercle and angle
Innervation - posterior rami of c8-t11
Main action - elevate ribs
Serratus posterior superior
Superior - nuchal ligament spinous process of c7-t3
Inferior - superior borders of 2-4 ribs
Innervation - 2-5 intercostal nerves
Main action - elevate ribs
Serratus posterior inferior
Superior - inferior borders of 8-12 ribs near their angles
Inferior - spinous process of t11-L2
Innervation - 9-11 intercostal nerves subcostal (t12)
Main action - depress ribs
Mediastinum
Covered on each side of the pleura and contains the thoracic viscera and structures except the lungs
Extends from the superior thoracic aperture to the diaphragm inferiorly and from the sternum and costal cartilages
Highly mobile region because it consists primarily of hollow visceral structures
