Thorax Flashcards
How many ribs are there?
12
What are the true ribs?
First 7 which are connected anteriorally by costal cartilage to the sternum
What are the false ribs?
Ribs 8-12
Vertebrochondrial ribs
Indirectly connected to the sternum and attached to each other / rib 7 by costal cartilage
Free floating ribs
Ribs 11 and 12
Typical ribs
Ribs 3-9
Typical in structure
Atypical ribs
1, 2, 10-12
What are the 3 parts of the sternum, list superior to inferior?
Manubrium
Body
Xiphoid process
What is the jugular notch?
The concave center of the manubrium of the sternum
Superior border of the sternum
What is the middle part of a typical rib called?
The shaft or body
What is the angle of a typical rib?
Where the rib bends sharply anteriorally
What does the costal groove contain?
1) Intercostal vein
2) Intercostal artery (VAN)
3) Intercostal nerve
Label the parts of a typical rib from medial to lateral on the posterior side
head
neck
tubercle
What does the tubercle of a rib connect to?
the body
Which rib has the scalene tubercle?
First rib
Scalene tubercle and veins/arteries
Subclavian vein crosses the first rib anterior to the scalene tubercle
Subclavian artery crosses the first rib posterior to the scalene tubercle
Brachial plexus and ribs
Brachial plexus crosses the first rib posteriorally to the scalene tubercle
What makes the second rib atypical?
rough area on its superior surface
the tuberosity for the serratus anterior muscle
What makes ribs 10, 11, and 12 atypical in structure?
Single facet head for bodies of corresponding vertebrae
Is the first rib’s head single facet?
Yes
How many facets do typical ribs have to connect with vertebrae?
Two facets
How do the external intercostal muscles pass?
Pass inferiorally and medially from the rib above to the rib below
How do the fibers of the external intercostal muscles travel?
Obliquely
This is opposite of the internal and intermost intercostal muscles
How do the internal intercostal muscles pass?
Inferiorally and posteriorally from rib above to rib below
What are the 3 intercostal muscles?
External, internal and innermost
What is the nerve supply for the intercostal muscles?
Intercostal nerves supply all 3 intercostal muscles
What is the distinguishing feature of the innermost intercostal muscles?
They are separated from the internal intercostal muscles by the neurovascular bundles
Where is the neurovascular plane of the thoracic wall?
Between the middle and deepest layers of muscles
Subcostal muscles
Span two intercostal spaces
Pass inferiorally
Parallel to internal intercostal muscles
Transversus thoracis
Four or five slips of muscles that fan out from inferior part of sternum to costal cartilages 2-6
Ventral rami
Nerves that supply the anterior / ventral portion of the trunk
Dorsal rami
Nerves that supply the posterior / dorsal portion of the trunk
How many vertebrae make up the thorax?
12
Thoracic nerves
Refers to the 12 pairs of nerves that arise from the 12 vertebrae
What is true of the thoracic nerves?
They are highly segmental and will split into dorsal and ventral rami quickly
Subcostal nerve
The 12th ventral ramus
What do most spaces contain in terms of arteries?
One large posterior intercostal artery
Two small anterior intercostal arteries
How are the posterior intercostal arteries grouped?
- First two spaces
- Lower nine spaces
How are the anterior intercostal arteries grouped?
- Upper six spaces
- Lower anterior intercostals 7-9
- Absent from the two lower intercostal spaces
How many intercostal spaces are there?
11
Posterior intercostal arteries - first 2 spaces
branches of the supreme intercostal artery
which itself is a branch of the costocervical trunk of the subclavian artery
Posterior intercostal arteries - lower 9 spaces
Direct branches from the thoracic aorta
Anterior intercostal arteries - upper 6 spaces
Branches of the internal thoracic artery
anastomose laterally with the posterior intercostal arteries.
anastomose meaning
linked at
Anterior intercostal arteries - lower anterior intercostals
Spaces 7-9
Branches of the musculophrenic artery
What are intercostal spaces 10-11 supplied by?
Only posterior intercostal arteries
What is important to note of the lower posterior intercostal and subcostal arteries?
they continue into the abdominal wall along with the nerves
Do the anterior intercostal arteries continue into the abdominal wall?
No because they stop at the 9th intercostal space
Where is the internal thoracic artery located?
Lateral to the sternum, anterior to the transversus thoracis muscle
What does the internal thoracic artery branch into?
Superior epigastric artery
Musculophrenic artery
*These are both terminal branches
Pericardiophrenic artery
A branch of the internal thoracic artery
Runs with the phrenic nerve
supplies the pericardium, diaphragm and part of pleura
Perforating branches
branches of the internal thoracic artery
pass to the skin with the intercostal nerves
contribute to blood supply of the breast and enlarged during lactation
What is true of all arteries?
They are accompanied by corresponding veins
Where do the posterior intercostal veins empty into?
azygous and hemiazygous veins
Where do the anterior intercostal veins drain into?
Drain into the musculophrenic vein or the internal Thoracic vein.
Where does the internal thoracic vein drain into?
Drains into the brachiocephalic vein.
Where do the external intercostal muscles extend from?
From the rib tubercle posteriorly to the costochondral junction anterioraly
Costochondral joint
the junction between a rib and its costal cartilage
Where do the internal intercostal muscles extend from?
From the sternum anteriorly to the angles of ribs posteriorly
Angle of rib
Where the shaft bends sharply
Which way do ribs bed?
Anteriorly
What is the joint between the sternum and a rib called?
Sternocostal joint
