1- Introduction Flashcards
What defines two distinct apertures in the thoracic cage? What are these structures?
The boney structures define the two distinct apertures in the thoracic cage. These structures are:
1) Superior thoracic aperture (Inlet)
2) Inferior Thoracic Aperture (Outlet)
What does the thoracic cavity contain?
Thymus Heart Lungs Distal part of trachea Most of esophagus
What are the boundaries and contents of the Thoracic Inlet?
Boundaries:
- First pair of ribs and cartilage
- Manubrium sterni (superior border)
- First Thoracic Vertebra (T1)
Contents:
- APEX of the lungs!
- Trachea
- Esophagus
- Vagus N. (CN X), phrenic n. (C3,4,5)
What are the boundaries and contents of the thoracic outlet (inferior thoracic aperture)?
Boundaries:
- the 12th thoracic vertebra (T12)
- the 12th pair of ribs
- costal margin = costal cartilages 7-10
Contents:
NOTHING!
What are important landmarks of the thoracic cage?
- Xiphoid process
- Sternal angle of Louis
- Costal cartilage of 2nd rib/manubriosternal joint
- Angle of Louis
What level is the xiphoid process?
T10 or T11
Where is the sternal angle?
Lower border of T4
Where is the costal cartilage of the 2nd rib?
With the manubrialsternal joint
What is the angle of Louis and what is important about it?
The angle of Louis is the angle ormed between the Manubrium and the body of the sternum (manubrialsternal joint).
The angle of Louis marks the 2nd costal cartilage for counting intercostal spaces.
It denotes the level of the:
1) Aortic arch and branches of the aortic arch
2) bifurcation of the trachea (carina)
3) T4/T5 intervertebral disc
What part of the body is the thorax?
The superior part of the trunk between the neck and the abdomen.
Describe the shape of the ribs in the thoracic cage?
THe ribs are narrow, curved, flat bones
How many ribs are there? What’s are special aspects of the ribs?
12 pairs of ribs:
- Longest: Rib 7
- Shortest: Rib 12
- Ribs 3-9 : TYPICAL RIBS
- Ribs 1,2,10,11,12 : ATYPICAL RIBS
- Ribs 1-7 articulate directly with the sternum through their costal cartilages and are TRUE RIBS
- Ribs 8,9,10 : share a common costal cartilage and are the FALSE RIBS
- Ribs 11-12 : do not articulate anteriorly and end among the muscles of the body wall = FLOATING RIBS
Where is the costal groove?
Located on the inferior aspect of the ribs
What is the function of the costal groove?
To shelter the intercostal neurovascular bundle (vein, artery, nerve - VAN)
Describe the first rib and nearby contents. What is particular about the first rib?
The first rib is short and broad, forms part of the thoracic inlet, and it has a groove for the SUBCLAVIAN vein and artery.
Identify the grooves for the subclavian artery and vein on the first rib
Page 8
Identify the tubercle for muscle attachment on the second rib
Page 8
Identify the shaft and tubercle on the second rib
Page 8
Identify the costal angle, head and tubercle on the 11th rib
Page 8
Identify the costal angle on a typical rib
Page 7
What is the anatomy of an intercostal space (I.e. contents and boundaries)
Boundaries
Intercostal mm: external and innermost
Contents:
Internal m
Vein
Artery nerve
What are the functions of the thoracic cage?
Protection of internal organs
Framework for attachment of muscles
Assists in respiration
During inspiration, how do the walls of the thoracic wall move?
The thorax widens as the ribs elevate.
As the ribs elevate, the middle parts of the lower ribs move laterally (“bucket handle movement”)
As the upper ribs are elevated, the anterior-posterior diameter of the thorax is increased (“pump handle movement”) w/ greater excursion (increase) occurring inferiorly.
Overall increase in AP and transverse diameters of the thoracic cage
What is bucket handle movement?
The lateral movement of the middle parts of the lower ribs when they are elevated
