Overview of the Thorax Flashcards
What forms the thoracic cage?
12 pairs of ribs
Sternum
Costal cartilages
12 thoracic vertebrae
What are the costocartilages attached to?
The sternum and the ribs
What are the components of the sternum?
Jugular notch (on the manubrium)
Clavicular notch (on the manubrium)
Manibrium
Sternal angle (between the manibrium and the body)
Body
Xiphisternal junction (between xiphisternal and the body)
Xiphoid Process
What are the special features of the thoracic vertebrae?
- Long inferiorly angled spinous processes
- Costal facets (except the last 2 or 3 thoracic vertebrae) which exist on the transverse process.
- Two demifacets located laterally on the bodies of vertebrae T2-T9
Which thoracic vertebrae bodies contain demifacets?
How many are there? How do they articulate with the ribs.
T2-T9.
There is a superior demifacit and an inferior demifacet.
The superior facet articulates with the head of the corresponding rib (i.e same rib number), while the inferior facet articulates with the head of the rib below it (higher number)
How does the head of the rib articulate with the thoracic vertebrae? What are the parts of the head of the rib?
There is an:
- Inferior articular facet
- Superior articular facet
The inferior facet corresponds with the vertebrae of its same number, while the superior facet corresponds with the vertebral body above it.
Therefore, if we are dealing rib 7 the inferior aspect of the rib will articulate with vertebral body 7 while the superior aspect will articulate with the vertebral body above it (lower number) 6
Which ribs are considered typical ribs?
T3-T9
Which ribs are considered True ribs?
First rib through the 7th rib
Which ribs are considered false ribs? What does it mean to be a false rib?
Ribs eight through ten. It means they don’t have their own insertion on to a costocartilage. Instead they share a costacartilage.
Which ribs are considered atypical ribs?
1, 2, 10, 11, and 12
What are the components of the first rib? (atypical)
- Scalene tubercle
2. Single facet for articulation only with T1 vertebrae
What are the components of the second rib? (atypical)
Tubercle for origin of serratus anterior muslce
What are the components of the tenth rib? (atypical)
Only one facet for articulation with only one vertebrae
What are the components of the 11th and 12th rib? (atypical)
They have no necks or tubercles
They are free floating
They articulate with only one vertebrae
What Thoracic bodies are at the same level as the manibrium?
T3 and T4
Where can the jugular notch be palpated?
Palpated at the T2 vertebral level
Where can the sternal Angle (of Louis) be palpated?
Palpated at the vertebral T4 level
Where is the Xiphoid process located?
Located at the level of T10
What is the most anterior part of the bony part of the chest?
Sternal angle (manubriosternal joint)
How does communication occur between the thoracic cavity and the abdomen and neck?
Through the Superior and Inferior Thoracic aperture.
What are the structures passing through the superior thoracic aperture?
Trachea
Esophagus
Nerves
Blood Vessels that either supply or drain the head and neck.
What are the structures passing through the inferior thoracic aperture?
Inferior Vena Caval Hiatus (T8) Esophageal Hiatus (T10) Aortic Hiatus (T12)
What are the various intercostal muscles? (4)
- External Intercostal
- Internal Intercostal
- Innermost Intercostal
- Transversus Thoracic
Which intercostal muscle is on the inside of the rib cage?
Transverse Thoracis
What is the function of the external intercostal muscle?
Raises ribs on inspiration
What is the function of the internal intercostal muscles?
Lowers the ribs on expiration
What is the function of the innermost intercostal muscles?
Raises the ribs on inspiration
Which muscle fibers are oriented in a hands in pocket way?
External intercostal muscles
Which muscle fibers are oriented in a hands in back pocket way?
Innermost intercostal muscles
Which muscle fibers are oriented in a praying hands way?
Internal intercostal musclt
List intercostal muscles from anterior to posterior
- External Intercostal
- Internal Intercostal
- Innermost Intercostal
Which muscle is the most powerful respirator?
The diaphragm
What nerve is the Diaphragm innervated by?
What does it attach to?
Where does it insert?
The phrenic nerve
Xiphoid process, lower 6 costal cartilages, and the L1-L3 vertebrae
The central tendon
What inserts into the central tendon? What happens to it?
The Diaphragm. It functions to draw the central tendon down and forward during inspiration
What are the three main openings in the diaphragm?
- Inferior vena cava (T8)
- Esophagus (T10)
- Aorta (T12)
Note: They are also in order from anterior to posterior
Remember the mneumonic
I Ate Ten Eggs At Noon
What are the movements of the thoracic cage?
Vertical Movement
Transverse Movement
Anteroposterior Movement
What ribs does the anteroposterior use when moving?
Uses ribs 2-6 at the costal verterbral joints. pump handle motion down
What movement is caused by the movement of the diaphragm?
Vertical movement
Bucket handle motion causes which movement?
Intercostal muscle movement
Where does the INTERCOSTAL vein, nerve, and artery of the thoracic wall exist?
Between the ribs on each rib (inferior rin and superior rib) always in the V, A, N order, that is the Vein touches the rib.
What does the intercostal nerve communicate with?
Rami communications via the sympathetic trunk
Where does anastomoses of the intercostal arteries takes place?
Posterior Wall?
Anterior Wall?
On both sides of the sternum.
Posterior Wall: Posterior intercostals
Anterior Wall: Anterior intercostals
Where do the posterior intercostal arteries come from?
They are branches of the aorta and costocervical trunk
Where do the anterior intercostal arteries come from?
They are branches of the internal thoracic and musculophrenic arteries.
How do the intercostal veins run in comparison to the intercostal arteries?
They run in the opposite direction
Describe the intercostal venous system.
There are two veins on the left side called Inferior and Superior Hemizygous veins and one on the right side called the Azygous vein.
All dump into the Azyogous vein
What percent of muscles does the ventral rami innervate?
95%
What muscle group does the dorsal rami innervate?
The true back muscles
What nerve are intercostal muscles innervated by?
The ventral rami of the thoracic spinal nerves
What is the landmarks for the clavicles and the jugular notch?
C4
What is the landmarks for the sternal angle?
T2 dermatome
What is the landmarks for the nipples?
T4 dermatome
Mediastinum information. What is the dividing factor?
The sternal angle divides the two halves.
- Superior Mediastinum
- Inferior Mediastinum (superior to the diaphragm)
- Anterior Mediastinum
- Middle Mediastinum
- Posterior Mediastinum
What can be found in the Superior Mediastinum?
Thymus Brachiocephalic veins Superior Vena Cava Phrenic Nerve Vagus Nerve Aortic arch and branches Trachea Esophagus
What can be found in the Anterior Mediastinum?
Thymus
Sternopericardial ligaments
What can be found in the Middle Mediastinum?
Pericardial cavity/heart
Great vessels
Phrenic nerve
Roots of the lungs
What can be found in the posterior Mediastinum?
Esophagus Descending Aorta and branches Azygous vein Thoracic Duct Sympathetic Chain Splanchnic nerve
Discuss the vagus nerve plexus.
There is a vagus nerve plexus around the esophagus that continue around the heart and lungs.
Left side: covers more of the anterior
Right side: covers more of the posterior
Where does the phrenic nerve go?
Straight to the diaphragm