Chest wall Flashcards
1
Q
What is the thorax?
A
Thorax is the part of the body found inferior (below) to the neck and superior (above) to the abdomen
2
Q
what is the thoracic cavity outlines and bounded by
A
The thoracic cavity is essentially outlined and bounded by the bony skeleton
- Sternum - anteriorly
- Ribcage (ribs + costal cartilages) - laterally
- Thoracic vertebrae – posteriorly
- Diaphragm – inferiorly (red dotted line)
3
Q
What is the sternum, and where is it located?
A
The sternum is a flat and elongated bone found on the anterior aspect of the thoracic cage. It offers protection for much of the heart and other mediastinal viscera.
4
Q
What are the three parts of the sternum?
A
Manubrium
Body
Xiphoid process
These parts are linked together by secondary cartilaginous joints.
5
Q
What is the manubriosternal joint, and what does it form?
A
The manubriosternal joint is a symphysis joint that forms the sternal angle, an important surface landmark projecting as a ridge.
6
Q
Why is the sternal angle clinically significant?
A
The sternal angle serves as an important surface landmark for identifying rib levels and anatomical structures within the thoracic cavity.
In the elderly, this joint begins to cease, and this impedes breathing.
7
Q
What is the xiphisternal joint, and what is its characteristic?
A
The xiphisternal joint is a synchondrosis joint. It typically appears fused along with the manubriosternal joint in adults.
8
Q
What are 3 the anatomical features of the manubrium?
A
The manubrium includes the:
Clavicular notch
First costal notch
Jugular notch
9
Q
Describe the body of the sternum and its key features.
A
The body of the sternum includes the:
Sternal angle
Second through seventh costal notches
10
Q
What is the xiphoid process, and where is it located?
A
The xiphoid process is the smallest and most inferior portion of the sternum.
11
Q
What joints of the sternum typically appear fused in adults?
A
The xiphisternal joint and the manubriosternal joint typically appear fused in adults.
12
Q
What is the joint between the manubrium and the body?
A
- The joint between the manubrium and the body is the sternal angle (or angle of Louis).
- This joint forms an important hinge for movements of the rib cage.
13
Q
What is the significance of the sternal angle in rib and intercostal space counting?
A
The sternal angle marks the articulation of the second rib, which is used as a reference point for counting ribs and intercostal spaces.
14
Q
How does the sternal angle divide the mediastinum?
A
The sternal angle divides the mediastinum into the superior mediastinum and the inferior mediastinum.
15
Q
What 4 anatomical structures are marked by the level of the sternal angle?
A
The sternal angle marks the level of:
- Bifurcation of the trachea
- End of the ascending aorta
- Beginning and end of the arch of the aorta
- Beginning of the superior vena cava
16
Q
How many pairs of ribs do humans have, and how are they classified?
A
Humans have 12 pairs of ribs, which can be classified in two different ways.
17
Q
Which ribs are considered “typical ribs”?
A
Ribs 3rd to 9th are considered “typical ribs.”
18
Q
What are the 2 features of the head of a typical rib?
A
The head of a typical rib has two facets (flat surfaces)
1. One facet articulates with the numerically corresponding vertebra.
2. The other facet articulates with the vertebra superior to it.
19
Q
What is the function of the neck in a typical rib?
A
The neck connects the head of the rib with its body.
20
Q
What is the role of the tubercle in a typical rib?
A
The tubercle has a facet (flat surface) that articulates with the transverse process of the numerically corresponding vertebra.
21
Q
The body of a typical rib has two key features:
A
- At the costal angle, the rib turns anterolaterally.
- It has a costal groove along the inferior border that protects the intercostal nerve and vessels.
22
Q
What are atypical ribs, and which ribs are classified as such?
A
Atypical ribs include the 1st, 2nd, and 10th–12th ribs because their structure and articulations differ from the typical ribs.
23
Q
Describe the features of the 1st rib.
A
The 1st rib is short and flat, with its head articulating only with the T1 vertebra. It also has the following notable features:
Groove for the subclavian artery
Groove for the subclavian vein
Tubercle for the anterior scalene muscle
24
Q
Describe the features of the 2nd rib.
A
The 2nd rib has the following characteristics:
Two articulating facets at its head for articulation with the bodies of T1 and T2 vertebrae.
A tuberosity for the serratus anterior muscle
25
What is unique about the 10th–12th ribs?
The 10th–12th ribs (and sometimes the 10th rib) have only one facet on their heads and articulate with a single vertebra.
26
How many pairs of ribs do humans have, and how are they classified?
Humans have 12 pairs of ribs, classified into:
True ribs (1st–7th)
False ribs (8th–10th)
Floating ribs (11th and 12th)
27
What are true ribs, and how do they attach to the sternum?
True ribs (vertebrosternal ribs) are the 1st to 7th ribs. They attach directly to the sternum through their own costal cartilages.
28
What are false ribs, and how do they attach to the sternum?
False ribs (vertebrochondral ribs) are the 8th, 9th, and 10th ribs. They attach indirectly to the sternum as their costal cartilages connect to the cartilage of the rib above them.
29
What are floating ribs, and what distinguishes them from other ribs?
Floating ribs (11th and 12th ribs) have no connection to the sternum. They are free at their anterior ends and lack costal cartilage.
30
What are the costal margins, and where are they located?
The costal margins (C) are the inferior edges of the thoracic cage formed by the cartilages of the 7th to 10th ribs.
31
What are intercostal spaces, and how are they named?
Intercostal spaces are the spaces between adjacent ribs. They are named according to the rib forming the superior border of the space (e.g., the space below the 1st rib is the 1st intercostal space).
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What is the spinous process of a vertebra?
The spinous process is a bony projection extending posteriorly from the vertebral arch. It serves as an attachment point for muscles and ligaments.
40
What are transverse processes, and how many are found on each vertebra?
Transverse processes are lateral bony projections that extend from the vertebral arch. Each vertebra has two transverse processes, which serve as attachment points for muscles and ligaments.
41
how many articular processes are there?
4
42
What is the vertebral arch, and what are its components?
The vertebral arch is a bony structure that encloses the spinal cord. It consists of two parts:
Pedicle: The portion connecting the vertebral body to the transverse process.
Lamina: The portion connecting the transverse process to the spinous process.
43
What is the vertebral foramen, and what is its function?
The vertebral foramen is the central opening formed by the vertebral arch and the vertebral body. It provides a protective passageway for the spinal cord.
44
What is the vertebral body, and what is its primary function?
The vertebral body is the largest, anterior part of the vertebra. Its primary function is to bear weight and provide structural support to the spinal column.
45
How many thoracic vertebrae are there, and what is their primary role?
There are 12 thoracic vertebrae. Their primary role is to support the rib cage and serve as an attachment point for the ribs, contributing to the structure and protection of the thoracic cavity.
46
What are costal facets (demifacets), and where are they located?
Costal facets, also known as demifacets, are located on the vertebral bodies of thoracic vertebrae. They typically have a superior and inferior facet, which articulate with the facets on the head of the ribs.
47
What is the function of costal facets on transverse processes?
The costal facets on the transverse processes of thoracic vertebrae articulate with the tubercles of the ribs, helping to stabilize the rib cage.
48
What is the superior thoracic aperture, and what are its 3 boundaries?
Posteriorly: T1 vertebra
Laterally: 1st pair of ribs and their costal cartilages
Anteriorly: Superior border of the manubrium
It transmits structures such as the trachea, oesophagus, nerves, and blood vessels.
49
What is the inferior thoracic aperture, and what are its 4 boundaries?
The inferior thoracic aperture is the lower opening of the thoracic cavity. Its boundaries are:
Posteriorly: T12 vertebra
Posterolaterally: 11th and 12th pairs of ribs
Anterolaterally: Joint costal cartilages of ribs 7-10
Anteriorly: Xiphisternal joint
It transmits structures such as the oesophagus, aorta, and inferior vena cava.
50
What 4 structures pass through the superior thoracic aperture?
Trachea
Oesophagus
Nerves (e.g., vagus and phrenic nerves)
Blood vessels (e.g., subclavian arteries and veins)
51
What 3 structures pass through the inferior thoracic aperture?
Oesophagus
Aorta
Inferior vena cava
52
What are the three main openings in the diaphragm located at the inferior thoracic aperture?
Caval opening (for the inferior vena cava)
Oesophageal hiatus (for the oesophagus)
Aortic hiatus (for the aorta)
53
What are costovertebral joints?
Costovertebral joints are the joints where ribs articulate with the vertebral column at two points
54
Which two joints do the Costovertebral joints articulate with in the ribs at the vertebral column?
Joints of the heads of ribs: Where the head of a rib articulates with the costal facets on the vertebral bodies.
Costotransverse joints: Where the costal tubercle of a rib articulates with the costal facets on the transverse processes.
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What movement occurs in the superior and middle costotransverse joints?
In the superior and middle costotransverse joints, the ribs and sternum move in a **pump-handle motion**, involving:
Elevation and depression of the sternal ends of the ribs and sternum, increasing the anterior-posterior diameter of the thoracic cavity.
63
What movement occurs in the lower costotransverse joints?
In the lower costotransverse joints, the ribs move in a **bucket-handle motion**, involving:
Elevation and depression of the lateral portions of the ribs, increasing the transverse diameter of the thoracic cavity.
64
How do the pump-handle and bucket-handle movements contribute to respiration?
These movements increase the thoracic cavity's diameter in two axes during inspiration:
Anterior-posterior axis (pump-handle motion).
Lateral axis (bucket-handle motion).
This expansion allows the lungs to fill with air more effectively.
65
How does the rib cage change in dimensions during respiration?
During inspiration:
The rib cage increases in diameter both in the anterior-posterior axis (via pump-handle motion) and the lateral axis (via bucket-handle motion).
66
What is the axis of movement for the pump-handle motion, and which ribs are involved?
The axis of movement for the pump-handle motion is along the neck of the rib. It primarily involves the upper ribs and the sternum.
67
What is the axis of movement for the bucket-handle motion, and which ribs are involved?
The axis of movement for the bucket-handle motion is along the costotransverse joints. It primarily involves the lower ribs.
68
what kind of movement does middle costotransverse joints show?
rotation
69
what kind of movement does lower costotransverse joints show?
gliding - elevation and depression
70
what is the primaru function of pectoralis major
the pectoralis major muscle is responsible for shoulder joint movement primarily
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What are the 3 proximal attatchments of the pectoralis major
Clavicular part- medial half of clavicle (C)
sternocostal part - sternum and superior six costal cartilages (S)
abdominal part - external oblique aponeurosis (A)
77
what is the Distal attachment of pectoralis major
Distal attachment: lateral crest of intertubercular groove of the humerus
78
what is the proximal attachment of the pectoralis minor?
Proximal attachment: ribs 3-5
79
what is the distal attachment of the pectoralis minor?
distal attachment: coracoid process of the scapula
80
what is pectroalis major innervated by?
lateral and medial pectoral nerves
81
what is pectoralis minor innervated by?
medial pectoral nerve
82
What is the shared function of the Pectoralis major and Pectoralis minor?
Both assist in respiration when the shoulder girdle is fixed.
83
what is the serratus anterior innervated by?
long thoracic nerve
84
What is the proximal attachment of the Serratus anterior?
The proximal attachment of the Serratus anterior is the lateral aspects of ribs 1-9.
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What is the distal attachment of the Serratus anterior?
The distal attachment of the Serratus anterior is the anterior surface of the medial border of the scapula.
86
What is the function of the Serratus anterior in respiration?
The Serratus anterior helps elevate ribs when the shoulder girdle is fixed, which assists in respiration.
87
what is the scalene muscle innervated by
ventral rami of cervical spine nerves 3-8
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What is the proximal attachment of the Scalene muscles?
The proximal attachment of the Scalene muscles is the transverse processes of C3-C7 vertebrae.
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What is the distal attachment of the Scalene muscles?
The distal attachment of the Scalene muscles is ribs 1 and 2.
90
what is the action of scalene muscles in respiration
elevate upper ribs in inspiration
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what is the Abdominal oblique muscles innervated by
The Abdominal oblique muscles are innervated by the anterior rami of thoracic and lumbar spinal nerves.
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What is the Rectus abdominis muscle innervated by?
The Rectus abdominis is innervated by the anterior rami of thoracic spinal nerves.
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What is the action of the Abdominal oblique muscles and Rectus abdominis?
Both the Abdominal oblique muscles and Rectus abdominis work to **compress the abdomen and assist in expiration.**
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External Oblique
(TIP - look at the direction its running in, its going downards)
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internal oblique
(TIP - look at the direction its running in, its going upwards)
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TA = Transversus Abdominis
RA = Rectus Abdominis
97
What are the three layers of intercostal muscles?
External intercostals
Internal intercostals
Innermost intercostals
98
Where do the External intercostal muscles attach
The External intercostal muscles run from the **costal tubercle** (on the back of the rib) to the **costochondral junction** (where the rib meets the costal cartilage in the front).
99
What is the orientation of the External intercostals (EI)?
The External intercostals run antero-inferiorly from the rib above to the rib below (like hands in pockets).
Anteriorly, the muscle fibers are replaced by a membrane.
100
What is the orientation of the Internal intercostals (Int I)?
The Internal intercostals run postero-inferiorly from the rib above to the rib below.
Posteriorly, the muscle fibers are replaced by a membrane.
They are deep and run at right angles to the external intercostals.
101
What are the Innermost intercostals?
The Innermost intercostals are essentially the deep parts of the internal intercostals.
They are separated from the internal intercostals by intercostal nerves and vessels.
102
Where do the internal intercostal muscles attach
The Internal intercostal muscles run from the **costal angle** (at the back of the rib) to the **sternum** (at the front of the chest).
103
Which intercostal muscle is active during inspiration?
The External intercostal muscle is active during inspiration
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What is the role of all intercostal muscles during respiration?
All intercostal muscles help to keep the intercostal spaces rigid and prevent them from blowing out during respiration.
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What is disputed about the role of the Internal and Innermost intercostals in respiration?
It is disputed whether the Internal and Innermost intercostals play a role in elevating the ribs during inspiration.
It has also been suggested that the Internal and Innermost intercostals help to depress the ribs.
106
where is the diaphragm located
The diaphragm is located at the floor of the inferior thoracic aperture.
107
what is the primary role of the diaphragm
It is the primary muscle of inspiration by flattening and increasing the intrathoracic volume, which decreases the pressure.
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what kind of process is expiration and what is it brought about by
Expiration is passive and is brought about by the recoil of the diaphragm and lungs.
109
What is the major content of an intercostal space?
The major content of an intercostal space is VAN, which stands for:
Vein
Artery
Nerve
These structures are arranged in this order from superior to inferior.
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Where are the VAN structures located in an intercostal space?
The VAN structures run along the inferior border of a rib in the costal groove.
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What is the purpose of an intercostal nerve block?
An intercostal nerve block targets the intercostal nerves
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What is the function of preganglionic sympathetic fibers in the intercostal nerves?
Preganglionic sympathetic fibers in the intercostal nerves communicate with the sympathetic ganglia via the white communicating ramus.
Postganglionic sympathetic fibers can return to the anterior ramus via the gray communicating ramus.
113
What do the lateral cutaneous branches of the intercostal nerves supply?
The lateral cutaneous branches supply the skin over the lateral aspects of the trunk.
They carry general somatic afferent fibers.
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What do the anterior cutaneous branches of the intercostal nerves supply?
The anterior cutaneous branches supply the skin over the anterior aspects of the trunk.
They carry general somatic afferent fibers.
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What is the role of the muscular branches of the intercostal nerves?
The muscular branches (unnamed) supply the intercostal muscles.
They carry general somatic efferent fibers.
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Where do the 1st and 2nd pairs of posterior intercostal arteries arise from?
The 1st and 2nd pairs of posterior intercostal arteries arise from the superior (supreme) intercostal artery.
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Where do the 3rd to 12th pairs of posterior intercostal arteries arise from?
The 3rd to 12th pairs of posterior intercostal arteries arise from the thoracic aorta directly.
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What is the 12th pair of posterior intercostal arteries referred to as?
subcostal arteries.
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Where do the 1st to 6th pairs of anterior intercostal arteries arise from?
internal thoracic artery.
120
Where do the 7th to 9th pairs of anterior intercostal arteries arise from?
musculophrenic artery.
121
What happens immediately after the anterior intercostal arteries arise from their respective sources?
After arising, the anterior intercostal arteries immediately divide into two branches to supply the superior and inferior parts of the same intercostal space.
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Where does the 1st pair of posterior intercostal veins drain into?
The 1st pair of posterior intercostal veins typically drain directly into the brachiocephalic veins.
123
Where do the 2nd and 3rd pairs (sometimes the 4th) of posterior intercostal veins drain into?
The 2nd and 3rd pairs (and sometimes the 4th) join to drain into the superior intercostal vein.
The left drains into the left brachiocephalic vein, and the right drains into the arch of the azygos vein.
124
Where do the 5th to 11th pairs and the subcostal vein (12th) drain into?
The 5th to 11th pairs and the subcostal vein (12th) drain directly into the azygos vein on the right side.
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Where do the 5th to 8th pairs and the 9th to 12th pairs of posterior intercostal veins drain into on the left side?
On the left side:
The 5th to 8th pairs drain into the accessory hemiazygos vein.
The 9th to 12th pairs drain into the hemiazygos vein.
126
What pattern do the anterior intercostal veins follow?
arteries.
127
Where do the anterior intercostal veins drain into?
The anterior intercostal veins drain into the accompanying veins (called venae comitantes) of the corresponding musculophrenic and internal thoracic arteries.
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What happens to the internal thoracic veins near the third costal cartilage?
The accompanying internal thoracic veins unite near the third costal cartilage to become the internal thoracic vein.
