Thoracic Wall Flashcards
Why is the sternum important?
It is a major site for RBC production
Which part of the sternum forms the jugular notch?
Manubrium
Which part of the sternum contains costal cartilage of the second rib that articulates directly with the manubriosternal joint?
Body
Which part of the sternum is cartilaginous at birth and slowly ossifies throughout life?
Xiphoid process
What structure is commonly broken during CPR?
Xiphoid process
What forms the sternal angle?
The articulation of the manubrium with the body of the sternum
What vertebral level is the sternal angle found?
The intervertebral disc between T4 and T5
What is the superior opening of the thoracic cage?
The superior thoracic aperture
What is the superior thoracic aperture bounded by? (3)
1) Manubrium
2) First rib
3) First thoracic vertebra
What is the inferior opening of the thoracic cage?
Inferior thoracic aperature
What is the inferior thoracic aperture bounded by? (5)
1) Xiphoid process
2) Costal margin
3) 12th rib
4) Distal end of 11th rib
5) 12th thoracic vertebra
What are the true ribs and how do they articulate with the sternum?
Ribs 1-7
Articulate with the sternum directly through their own costal cartilages
What are the false ribs and how to they articulate with the sternum?
1) Ribs 8-10: articulate with the sternum indirectly by attaching to the costal cartilage of the rib above
2) Ribs 11 and 12: not connected to the sternum at all
What are the typical ribs?
3-9
What are the atypical ribs?
1, 2, 10,11, and 12
What is the morphology of a typical rib? (6)
Head, neck, tubercle, angle, shaft, costal groove
Name the 3 functions of the thoracic cage.
1) Protection of thoracic and upper abdominal organs
2) Muscle attachments
3) Respiration
What is the 2nd most important muscle for inspiration?
External Intercostal Muscle
O, I, A, N of External Intercostal Muscle
O: lower border of ribs 1 to 11
I: upper border of ribs 2 to 12
A: elevates the ribs in inspiration
N: corresponding intercostal nerve
O, I, A, N of External Intercostal Muscle
O: lower border of ribs 1 to 11
I: upper border of ribs 2 to 12
A: elevates the ribs in inspiration
N: corresponding intercostal nerve
O, I, A, N of Internal Intercostal Muscle
O: the upperborder of ribs 2 to 12
I: the lower border of ribs 1 to 11
A: depresses the ribs in forced expiration
N: corresponding intercostal nerve
O, I, A, N of the Innermost Intercostal Muscle
O: the upper border of ribs 2 to 12
I: the lower of ribs 1 to 11
A: Depresses the ribs in forced expiration
N: corresponding intercostal nerve
O, I, A, N of the Subcostalis Muscle
O: inner surface of ribs near their angles
I: the muscle crosses a rib without inserting and then inserts into the rib above that
A: depresses the ribs in forced expiration
N: intercostal nerve
O, I, A, N of the Transversus Thoracis Muscle
O: posterior surface of lower sternal body and xiphoid process
I: inner surface of costal cartilages 2 to 6
A: depresses the ribs in forced expiration
N: intercostal nerve
What artery and its branches supplies the anterior aspect of the thoracic wall?
Internal thoracic artery
Name the branches of the internal thoracic artery. (4)
1) Pericardiacophrenic artery
2) Anterior intercostal arteries
3) Musculophrenic artery
4) Superior epigastric artery
What arteries supply the posterior aspect of the thoracic wall? (3)
1) Supreme (superior) intercostal artery
2) Third through eleventh posterior intercostal arteries
3) Subcostal artery
What vein drains the anterior aspect of the thoracic wall?
Internal thoracic vein (into the brachiocephalic vein)
What vein drains the posterior aspect of the thoracic wall?
Azygos system of veins
On the right and left side of the azygos system, what does the 1st posterior intercostal vein drain into?
The brachiocephalic vein
On the right side of the azygos system, what does the 2nd and 3rd posterior intercostal veins join together to form?
The superior intercostal vein, which drains into the azygos vein
On the right side of the azygos system, what does the 4th through the 11th posterior intercostal veins and subcostal vein drain into?
Directly into the azygos vein
On the left side of the azygos system, what does the 2nd and 3rd posterior intercostal veins join together to form?
The superior intercostal vein, which drains into the left brachiocephalic vein
On the left side of the azygos system, what does the 4th and 8th posterior intercostal vein join together to form?
The accessory hemiazygous vein, which drains into the azygous vein
On the left side of the azygos system, what does the 9th through the 11th posterior intercostal veins and the subcostal vein join to form?
The hemiazygous vein, which drains into the azygos vein
The azygous and hemiazygos veins represent the thoracic continuation of which veins?
The right and left ascending lumbar veins
What are the two nerves of the thoracic wall?
1) Intercostal nerves- the anterior primary rami of the first 11 thoracic spinal nerves
2) Subcostal nerve- the anterior primary ramus of the 12th thoracic spinal nerve
Name the 12 layers of the thoracic wall. (Figure 3.26B)
1) Skin
2) Superficial Fascia
3) Deep Fascia
4) Serratus anterior
5) External intercostal muscle
6) Internal intercostal muscle
7) Innermost intercostal muscle
8) Endothoracic fascia
9) Parietal pleura
10) Pleural cavity
11) Visceral pleura
12) Lung
What is the function of the endothoracic fascia?
To prevent the innermost intercostal muscle from rubbing against the parietal pleura
What is the thickening of the fascia over the apex of the lung called?
Suprapleural membrane
What structures does the typical intercostal space include?
1) Intercostal vein
2) Intercostal Artery
3) Intercostal Nerve
What two muscles is the typical intercostal space sandwiched in between?
The internal and innermost intercostal muscles
