Thoracic Wall Flashcards
Define costal margin. What is the significance of the costal margin?
lower boundary of the thoracic wall, formed by cartilages of 7th, 8th, 9th, and 10th ribs and ends of ribs 11 and 12. Lowest part of the costal margin formed by the 10th rib corresponds to the level of the 3rd lumbar vertebra.
How many ribs are there?
12 pairs
What are the three types of ribs and which ribs are they?
True ribs– upper 7 pairs have costal cartilage that attaches to sternum. Posteriorly attach to vertebrae.
false ribs - 8-10, attach indirectly to upper costal cartilages. Posteriorly attach to vertebrae.
floating/free ribs - 11 to 12. Have no anterior attachment. Posteriorly attach to vertebrae.
Define costotransverse joint
where facet of transverse process of vertebrae articulates with convex articular surface of tubercle of same number rib. It is a synovial joint. This occurs on upper 2-7 ribs. Allows for some rotation.
define costovertebral joint.
head of rib articules with body of same vertebra and upper vertebra
what are the three movements of the thorax during inspiration?
1) anterior-posterior (pump handle. ribs 2-6 at costotransverse joints. rotation. increase anterior/posterior dimension), 2) lateral/transverse (bucket handle) at costotransverse joints of ribs 7-10. gliding movement., 3) vertical dimension increased by contraction of diaphragm (diaphragm descends)
where does anterior/posterior movement occur?
at the costotransverse joints and at the joi nt between the body and manubrium of the sternum
Define the sternum joint.
between body of sternum and manubrium. Symphysis joint. The body of the sternum can move slightly forward with the movement of the upper ribs in the pump handle movement, anterior/posterior movement.
How would you describe the movement of the lower ribs (7-10)?
bucket handle/ lateral movement. Movement occurs at the costotransverse joints of rubs 7-10. Gliding movement.
Do the costovertebral joints have a lot of movement?
no. the heads of the ribs are closely attached to the superior costal facets on the bodies of the same vertebrae and the inferior facet of the vertebrae above it, allowing only slight gliding and rotation at the costovertebral joint.
Which direction does the diaphragm go with inspiration versus expiration?
expiration = ascend, inspiration = descend
What is the lower border of the thoracic cavity?
diaphragm
What innervates the diaphragm?
motor = phrenic nerve (C3, 4, and 5 ). sensory = phrenic in the central portion and intercostal and subcostal nerves in peripheral portion.
where would you insert a needle to remove fluid from the pleural cavity?
intercostal groove?
Where is the intercostal VAN located?
below the rib, near the costal groove.
What are the primary muscles of the thoracic wall?
external intercostal, internal intercostal, transversus thoracis, diaphragm.
What innervates the intercostal muscles?
intercostal nerves.
What is the action of the external intercostals and where do they attach?
they elevate and fix the ribs attach at the lower margin of upper eleven ribs to the superior border of the rib below.
how do the muscles of the internal intercostals relate to those of the external intercostals?
muscle fibers of internal intercostals are at right angles to external intercostals.
where do the inernal intercostals attach?
from ridge of inner surface of the rib and costal cartilage to the superior border of the rib below.
what is the function of the internal intercostals?
depresses ribs and fixes ribs.
can the internal intercostal be seen from under the external intercostal membrane?
yes
where can the internal intercostal muscles be seen from the inside?
under the innermost intercostal membrane
What are the three layers of the innermost layer of muscles in the thoracic wall?
transversus thoracis, subcostal, and innermost intercostals.