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.
What does the transversus thoracic do?
depresses upper ribs
what are the nerves of the thoracic wall?
intercostal nerves (ventral rami of T1-T12 thoracic spinal nerves). Subcostal nerve is below 12th rib (ventral rami of spinal nerve 12). These provide motor and sensory to the intercostal muscles and skin. T7-T12 also provide motor and sensory to the abdomen (continue as cutaneous nerves of the abdominal wall– lower abdominal wall also has innervation from lumbar plexus, L1). The nerves travel with the arteries and veins in costal grooves Intercostal nerves have somatic motor, somatic sensory, and sympathetic components.
What are the two large terminal branches of the internal thoracic artery and where do they go?
Superior epigastric continues downward onto abdominal wall under rectus abdominis. The musculophrenic heads laterally and downward, following the costal cartilage to supply the diaphragm and lower intercostal spaces
What are the veins of the thoracic wall?
anterior and posterior intercostal veins. The anterior drain into the internal thoracic vein, which empties into the brachiocephalic veins. The posterior drain into azygos system, which empties into the superior vena cava.
Define the boundaries of the thoracic cavity
1
what is the composition of the thoracic wall
1
describe the position and attachment of the diaphragm with understanding of the movement during respiration
1
describe the three movements that can increase the dimension of the thoracic cavity during respiration
1
identify the layers of the thoracic wall
1
what are the contents of the intercostal spaces?
1
what structures protect the thoracic organs?
ribs and sternum
What is an important landmark to identify or count the ribs on the thoracic wall?
Sternal angle, at rib #2
With severe pain present for an injured rib, what nerves would be involved?
somatic pain of intercostal nerves
What is the location of the blood vessels in the thoracic area?
in groove below rib
What is a major structure that is very important to increasing the vertical dimensions of the cavity during breathing?
diaphragm
If fluid accumulated in the pleural cavity after an injury, how many layers of muscle would a chest tube have to go through to reach the inside?
three layers (external and internal intercostals and transversus thoracis). Could be 4 if in the serratus anterior area.
Where would you insert a needle to avoid an artery?
above the rib
Define suprasternal notch and significance
superior margin of the manubrium, palpated between the ends of the clavicles in the midline. Can be used to determine the position of the lower border of the body of the second thoracic vertebra.
Define sternal angle and significance
angle made between the manubrium and body of the sternum. Lies opposite the interbertebral disc between the 4th and 5th thoracic vertebrae. Felt as a transverse ridge. Lateral movement of the finger will pass onto the second costal cartilage and the second rib.
what is the landmark for the second rib?
sternal angle
define xiphisternal joint and significance
attaches to the xiphoid process and body of sternum. Lies opposite body of the 9th thoracic vertebra. Joint forms inferior angle of the body of the sternum. Used to dtermine proper hand position for CPR. Costal margins of ribs 7-10 begin to extend inferiorly from this joint. The xiphoid process calcifies during aging.
how do you know where to place hands for CPR?
xiphisternal joint between xiphoid process and body of sternum.
how does the thoracic cavity communicate with the neck and upper limb?
through the superior thoracic aperture
what are the boundaries of the superior thoracic aperture?
posteriorly = T1 vertebra, laterally = 1st ribs and costal cartilages, anteriorly = superior border of the manubrium.
what is the significance of the superior thoracic aperture?
the trachea, esophagus, vessels, and nerves that communicate the neck and upper limb with the thoracic cavity pass through here
What is thoracic outlet syndrome? What is an example?
symptoms involving structures passing through the superior thoracic aperture. One example is costoclavicular syndrome, which involves symptoms of cold and pallor of the skin of the upper limb and diminished radial pulse. The subclavian artery becomes compressed between the clavicle and the first rib.
What is the inferior thoracic aperture?
communicates the thoracic cavity with the abdomen. Defined mainly by the diaphragm.
What are the boundaries of the thoracic wall and cavity?
upper = suprapleural membrane (located above pleural sac). Lower = diaphragm. Anterior = sternum. Posterior = vertebrae. Lateral = ribs.
Why is the sternal angle an important landmark?
1) second rib is attached here by costal cartilage, so useful for counting ribs. 2) arch of aorta and bifurcation of trachea lie deep to the sternal angle, 3) located at level of intervertebral disc between T4 and T5 vertebrae.
Where do the ribs attach to the vertebrae?
- The head of the rib articulates with the body of the corresponding vertebrae and the body of the vertebrae superior to it.
- The neck of the rib connects the head with the tubercle.
- The tubercle of the rib articulates with the transverse process of the corresponding vertebrae.
- -
What part of the rib is a common site for fractures?
angle
which part of the rib has a costal groove at the inferior surface?
shaft
where do the intercostal nerve, artery, and veins run?
costal groove (inferior of rib)
What segments of the body does the diaphragm divide?
thorax and abdomen
what is the chief muscle for respiration?
diaphragm
What is the diaphragm composed of?
peripheral muscular part and a central tendon. Forms two domes, right and left.
What are the three origins of the diaphragm? Where does the diaphragm insert?
Origins: 1) sternal part (R and L slips from posterior surface of xiphoid), 2) costal part (6 slips from deep surfaces of lower six ribs and costal cartilages), 3) vertebral part, from crura/legs of diaphragm and from arcuate ligaments. There are right and left crura.
Insertion: central tendon, which is fused to the fibrous pericardium.
What does the central tendon do?
helps support the heart
What is the most important function of the muscles of the thoracic wall?
stabilizing the ribs and thoracic cage during inspiration and expiration. Also contributes to posture.
Where do the muscles of the thoracic wall extend from?
vertebrae to sternum.
Where are the muscle sheaths of the thoracic wall muscles located?
between the ribs
the muscle fibers contained within a sheath may be replaces or continued by a ——-?
membrane that does not contain muscle fibers. The external intercostal muscle fibers are replaced anteriorly by an external intercostal membrane.
In which muscle layer do the nerves and arteries run?
between 2nd and 3rd
the fibers of the external intercostal muscles course in which direction?
inferiorly and anteriorly
what muscles are contained in the outermost, middle, and innermost layer of thoracic wall muscles?
outermost = external intercostals, middle = internal intercostals, innermost = transversus thoracis, innermost intercostal, and subcostal.
What do all of the intercostal muscles do in common?
act to fix the ribs
which intercostal muscles are replaced by a membrane anteriorly? posteriorly?
external intercostals are replaced by a membrane anteriorly near the sternum. This membrane overlays the internal intercostals. The internal intercostal muscle fibers are located from the sternum anteriorly and are eventually replaced posteriorly by a membrane.
what is the most anterior section of muscle of the innermost intercostal muscles?
transversus thoracis
what bony landmark are the transversus thoracis muscle fibers near?
sternum
What are the three sections of innermost intercostal muscles?
transversus thoracis, innermost intercostal, and subcostal
What are the main arteries involved in blood supply of the thoracic wall?
thoracic aorta, subclavian artery, and some from axillary artery.
The first two intercostal spaces are supplied by the _____ artery?
superior intercostal artery (between ribs 1-2 and 2-3). This artery is a branch of the axillary artery (from the subclavian)
Where is the blood supplied to the intercostal spaces?
below each rib in the costal groove
The intercostal spaces 3-4 through 11-12 are supplied by____ arteries?
anteriorly supplied by anterior intercostal artery off of the internal thoracic artery from the subclavian. Posteriorly supplied by he posterior intercostal arteries off of the thoracic aorta.
Blood supply to the inferior margin of the twelfth rib is from?
subcostal arteries, which are branches of the thoracic aorta
What are the major vessels of the anterior thoracic wall and where do they branch off?
internal thoracic arteries, from the subclavian.
What are branches of the internal thoracic artery (not the terminal branches)?
anterior intercostal arteries, anterior perforating arteries, pericardiophrenic arteries.
What is the significance of the anastomotic connection between the anterior and posterior intercostal arteries?
if there is a blockage of one artery, the blood could bypass the blockage by coming from the other source.
What nerves provide motor and sensory to abdomen?
T7-T12 provide motor and sensory to the abdomen (continue as cutaneous nerves of the abdominal wall) Lower abdominal wall also has innervation from lumbar plexus, L1.
What type of joint is the costovertebral joint?
synovial plane joint
What are the contents of the intercostal space from external to internal?
1) intercostal muscles, external and internal intercostal, 2) intercostal arteries, posterior and anterior, 3) intercostal veins, 4) intercostal nerves, 5) innermost intercostal muscles.
Where does the intercostal VAN run?
below the costal groove of the ribs between the second internal) and third (innermost) muscle layers of the thorax.
What are the components of the thoracic wall outermost to inner as it relates to the clinical application of a needle insertion to drain excess fluid in the pleural cavity?
skin, fascia *fat, connective tissue, serratus anterior, external intercostal, internal intercostal, area where vessels are, innermost intercostal, parietal pleura, pleural cavity, visceral pleura
