CHAPTER 2 : THORAX PART 1 : THORACIC WALL Flashcards

1
Q

Contained within the protective thoracic cage are the important
life-sustaining organs—lungs, heart, and major blood vessels.

In
addition, the lower part of the cage overlaps the upper abdominal
organs, such as the liver, stomach, and spleen, and offers them considerable protection.

A
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2
Q

Although the chest wall is strong,

  • *blunt or penetrating wounds** c**an injure the soft organs beneath
    it. **

T or F

A

True

This is especially so in an era in which automobile accidents,
stab wounds, and gunshot wounds are commonplace.

■■ Because of the clinical importance of the chest wall, examiners
tend to focus on this area.

Questions concerning the ribs and
their movements; the diaphragm, its attachments, and its function;
and the contents of an intercostal space have been asked
many times.

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3
Q

What is thorax?

A
The thorax (or chest) is the **region of the body between the
neck**and the**abdomen**
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4
Q

Describe the outside appearance of thorax.

A

It is flattened in front and behind
but rounded at the sides.

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5
Q

Define and describe the thoracic cage.

A

The framework of the walls of the
thorax, which is referred to as the thoracic cage.

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6
Q

Thoracic cage is formed
by the :

A
  • BEHIND :vertebral column
  • EITHER SIDE: the ribs and intercostal spaces on
  • FRONT: sternum and costal cartilages in
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7
Q

Superiorly, the thorax communicates with the
________

A

neck

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8
Q

inferiorly thorax is separated from the abdomen by
the______

A

diaphragm

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9
Q

The thoracic cage protects the lungs and
heart and affords attachment for the muscles of the thorax,
upper extremity, abdomen, and back.

A
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10
Q

What is the mediastinum?

A

The cavity of the thorax can be divided into a median

  • *partition, called the mediastinum**, and the laterally placed
  • *pleurae and lungs**.
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11
Q

What is a visceral pleura?

A

The lungs are covered by a thin membrane
called the visceral pleura, which passes from each
lung at its root (i.e., where the main air passages and blood vessels enter) to the inner surface of the chest wall, where it is called the parietal pleura.

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12
Q

How are the pleural cavities formed?

A

The cavity of the thorax can be divided into a median
partition, called the mediastinum, and the laterally placed pleurae and lungs.

The lungs are covered by a thin membrane
called the visceral pleura, which passes from each
lung at its root (i.e., where the main air passages and blood vessels enter) to the inner surface of the chest wall, where
it is called the parietal pleura. In this manner, two membranous
sacs called the pleural cavities are formed, one on
each side of the thorax, between the lungs and the thoracic
walls.

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13
Q

Structure of the Thoracic Wall

A
  • Sternum
  • Ribs
  • Costal Cartilages
  • Intercostal Spaces
  • Intercostal Muscles
  • Intercostal Arteries and Veins
  • Intercostal Nerves
  • Suprapleural Membrane
  • Endothoracic Fascia
  • Diaphragm
  • Internal Thoracic Artery
  • Internal Thoracic Vein
  • Levatores Costarum
  • Serratus Posterior Superior Muscle
  • Serratus Posterior Inferior Muscle
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14
Q

Sternum

A
  • body of the sternum
  • xiphoid process
  • sternal angle (angle of Louis),
  • xiphisternal joint
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15
Q

The sternum lies in the ___________

A

midline of the anterior chest wall.

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16
Q

What type of bone is the sternum?

A

It is a flat bone.

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17
Q

Sternum can be divided into three parts:

A
  • manubrium sterni,
  • body of the sternum,
  • and xiphoid process.
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18
Q

Describe manubirum.

A

The manubrium is the upper part of the sternum.

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19
Q

Manubrium articulates
with the body of the sternum at the ____________

A

manubriosternal
joint,

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20
Q

Manubrium
also articulates with the :

A
  • clavicles and
  • the 1st costal cartilage
  • and the upper part of the 2nd costal cartilages
  • on each side (see Fig. 2.1).
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21
Q

Sternum lies opposite the __________ vertebrae.

A

3rd
and 4th thoracic

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22
Q

The body of the sternum articulates above with the
manubrium at the manubriosternal joint and below with
the xiphoid process at the_______

A

xiphisternal joint.

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23
Q

The body of the manubrium articulates on each side,
with the ___________

A

2nd to the 7th costal cartilages

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24
Q

Discuss the xiphoid process.

A

The xiphoid process (see Fig. 2.1) is a thin plate of cartilage that becomes ossified at its proximal end during adult
life.

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25
No ribs or costal cartilages are attached to the xiphoid process. T or F
TRUE
26
The sternal angle (angle of Louis), formed by the articulation
**articulation of the manubrium with the body of the sternum,**
27
The sternal angle can be recognized by the **presence of \_\_\_\_\_\_\_\_\_\_\_\_**(Fig. 2.2).
**a transverse ridge** onthe **anterior aspect of the sternum**
28
The transverse ridge lies at the level of the \_\_\_\_\_\_\_\_\_\_\_
**2nd costal cartilage**, the point from **which all costal cartilages and ribs are counted**.
29
The sternal angle lies opposite the intervertebral disc between the \_\_\_\_\_\_\_\_\_\_\_vertebrae.
4th and 5th thoracic
30
The xiphisternal joint lies opposite the body of the \_\_\_\_\_\_\_\_\_\_ vertebra
ninth thoracic
31
Sternum and Marrow Biopsy Why is the Sternum a common site for marrow biopsy?
Since the sternum possesses red hematopoietic marrow throughout life, it is a common site for marrow biopsy. Under a local anesthetic, a wide-bore needle is introduced into the marrow cavity through the anterior surface of thebone.
32
The sternum **may also be split at operation** **to allow the surgeon to gain easy access** to the heart, great vessels, and thymus. T or F
True
33
Describe the Ribs.
There are **12 pairs of ribs,** all of which are attached posteriorly to the **thoracic vertebrae** ***L is the 12th letter of the alphabet*** ***Love is for heart*** ***L is for lungs*** ***Alll of which is contained in side the thoracic cavity***
34
The ribs are divided into three categories:
* True ribs: * False ribs: * Floating ribs
35
Describe the True ribs
The **upper seven pairs** are attached **anteriorly to** **the sternum by their costal cartilages.** **Upper Seven Heaven**
36
Describe the false ribs.
False ribs: The **8th, 9th, and 10th pairs** of **ribs are attached anteriorly**to each other and to the**7th rib by means of their costal cartilages and small synovial joints.**
37
Describe the floating ribs.
Floating ribs: The **11th and 12th** pairs **have no anterior** **attachment**
38
Desribe the TYPICAL RIB.
A **typical rib** is a **long, twisted, flat bone** having a **rounded, smooth superior border**and a**sharp, thin inferior border** (see Figs. 2.4 and 2.5).
39
Describe the inferior border of the ribs.
The **inferior border** overhangs and **forms the costal groove**, **which accommodates the intercostal** vessels and nerve. The anterior end of each rib is attached to the corresponding costal cartilage
40
What are the parts of the ribs?
A rib has a **head, neck, tubercle, shaft, and angle**
41
Describe the head of the rib.
The head has two facets for articulation with the **numerically corresponding vertebral body** and **that of the vertebra immediately above**
42
Discuss the neck part of the ribs.
The neck is a **constricted portion** situated **between the head and the tubercle**
43
Discuss the tubercle of the rib.
The tubercle is a **prominence on** * *the *outer* surface** of the rib **at the junction of the neck** * *with the shaft.**
44
What is the function of the tubercle?
It has a **facet for articulation** with the **transverse process of the numerically corresponding vertebra**
45
Describe the shaft of the rib.
The shaft is **thin and flattened** and **twisted on its long axis**. Its **inferior border has the costal** **groove.** **" nasa baba ng rib ang intercostal vessel so always remember to puncture or insert needle superiorly"**
46
Descirbe the angle of the ribs.
The angle is where the shaft of the rib bends sharply forward.
47
What is the ATYPICAL RIB?
First RIB.
48
**Why is the first rib clinically important?**
The **1st rib** is important clinically **because of its close relationship** **t**o the **lower nerves of the brachial plexus** and **the main vessels to the arm,** namely, the **subclavian artery and** **vein** (Fig. 2.6).
49
Describe the
50
Describe the first rib.
This rib is **small and flattened from above** **downward**.
51
What is attached to the upper surface and inner border of the first rib?
The **scalenus anterior muscle** is attached to its upper surface and inner border.
52
Anterior to the scalenus anterior,what vesses crosses the rib?
the **subclavian vein** crosses the rib
53
posterior to the scalenus anterior attachment, what crosses the ribs?
the **subclavian artery and the lower trunk of the brachial plexus** cross the rib and lie in contact with the bone.
54
Describe the Costal Cartilages
Costal cartilages are **bars of cartilage** **connecting the upper seven ribs to the lateral edge of the sternum** and the **8th, 9th, and 10th ribs to the cartilage immediately above.**
55
The cartilages of the **11th and 12th ribs** end in the \_\_\_\_\_\_\_\_\_(see Fig. 2.1).
abdominal musculature
56
What is the function of the costal cartilages?
The costal cartilages **contribute significantly to the elasticity** and **mobility of the thoracic walls**.
57
In old age, the costal cartilages tend to lose some of their flexibility as the result of superficial calcification. T or F
T
58
Joints of the Chest Wall Joints of the Sternum
* manubriosternal joint * xiphisternal joint
59
manubriosternal joint
The **manubriosternal joint** is a **cartilaginous joint** **between the manubrium** and the **body of the sternum.** A small amount of angular movement is possible during respiration
60
describe xiphisternal joint
The **xiphisternal join**t is a **cartilaginous joint between the xiphoid process (cartilage) and the body of the sternum.** T
61
The xiphoid process usually fuses with the body of the sternum during middle age. T or F?
T
62
Joints of the Ribs
* Joints of the Heads of the Ribs * Joints of the Tubercles of the Ribs * Joints of the Ribs and Costal Cartilages * Joints of the Costal Cartilages with the Sternum
63
Joints of the Heads of the Ribs The **1st rib and the three lowest ribs** have a s
single synovial joint with their corresponding vertebral body. '
64
For the **2nd to 9th ribs,** the head articulates by means of a :
synovial joint with the corresponding vertebral body and that of the vertebra above it (see Fig. 2.4). There is a strong intraarticular ligament that connects the head to the intervertebral disc
65
Joints of the Tubercles of the Ribs The tubercle of a rib articulates by means of a **synovial** **joint with the transverse process of the corresponding vertebra (see Fig. 2.4). (This joint is absent on the 11th and 12th ribs.)**
66
Joints of the Ribs and Costal Cartilages
These joints are cartilaginous joints. No movement is possible.
67
Joints of the Costal Cartilages with the Sternum The **1st costal cartilages** articulate with the (see Fig. 2.1).
manubrium, by cartilaginous joints that permit no movement
68
The **2nd to 7th costal cartilage**s articulate with \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
the lateral border of the sternum by synovial joints
69
In addition, the **6th, 7th, 8th, 9th, and 10th** costal cartilages articulate with
**one another along their borders** by **small synovial joints.**
70
The cartilages of the **11th and 12th ribs** are embedded in the \_\_\_\_\_\_\_\_\_
abdominal musculature.
71
Movements of the Ribs and Costal Cartilages
The **1st ribs and their costal cartilages are fixed** to the **manubrium and are immobile**.
72
The **raising and lowering** of the ribs during respiration are accompanied by movements in \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
**both the joints of the head** and **the tubercle, permitting the** **neck of each rib to rotate around its own axis.**
73
Openings of the Thorax What is the thoracic outlet?
The **chest cavity communicates with the root of the neck** through an opening called the **thoracic outlet.**
74
Why is it called thoracic outlet?
It is called an outlet **because important vessels and nerves emerge** **from the thorax** here to **enter the neck and upper limbs.**
75
What are the bounderies of the thoracic outlet?
* The **opening is bounded posteriorly** by the **1st thoracic** **vertebra,** * **laterally** by the **medial borders of the 1st ribs and their costal cartilages,** **and** * **anteriorly** by the **superiorborder of the manubrium sterni.**
76
Describe the opening of the thoracic outlet.
The opening is obliquely placed **facing upward and forward.** Through this small opening pass the esophagus and trachea and many vessels and nerves. Because of the obliquity of the opening, the apices of the lung and pleurae project upward into the neck
77
The thoracic cavity communicates with the abdomen through a **large opening.** What are the bounderieS?
The opening is bounded: * **posteriorly** by the **12th thoracic vertebra**, * **laterally** by the **curving** **costal margin**, and * **anteriorly** by the **xiphisternal joint.** Through this large opening, which is closed by the diaphragm, pass the esophagus and many large vessels andnerves, all of which pierce the diaphragm.
78
What is the Thoracic Outlet Syndrome?
The **brachial plexus of nerves (C5, 6, 7, and 8 and T1)** and the **subclavian artery and vein** are closely related to the **upper surface** **of the 1st rib** and th**e clavicle as they enter the upper limb** (see Fig. 2.6). It is here that the nerves or blood vessels may be compressed between the bones. Most of the symptoms are caused by **pressure on the lower trunk of the plexus producing** **pain down the medial side of the forearm** **and hand and wasting** **of the small muscles of the hand**. * *Pressure on the blood** * *vessels may compromise the circulation of the upper limb.**
79
Intercostal Spaces
The **spaces between** the ribs contain three muscles of **respiration.**
80
The s**paces between the ribs contain three muscles of respiration**:
* the external intercostal, * the internal intercostal, and * the innermost intercostal muscle.
81
The innermost intercostal muscle is lined internally by the \_\_\_\_\_\_\_\_\_\_\_\_\_\_
**endothoracic fascia**, which is **lined internally by the parietal pleura.**
82
The intercostal nerves and blood vessels run between the _____________ (Fig. 2.8).
intermediate and deepest layers of muscles
83
What is the arrangement of the intercostal vessels?
They are arranged in the following order from **above downward**: * intercostal vein, * intercostal artery, * and intercostal nerve **(i.e., VAN).**
84
Intercostal Muscles
* external intercostal muscle * anterior (external) intercostal membrane * internal intercostal muscle * innermost intercostal muscle
85
Describe the external intercostal muscle.
The external intercostal muscle **forms the most superficial** **layer.** Its fibers are directed **downward and forward** * *from the inferior border of the rib above to the superior** * *border of the rib below** (see Fig. 2.8).
86
The external intercostal muscle **extends forward to the costal cartilage** where it is replaced by an **aponeurosis**, the \_\_\_\_\_\_\_
anterior (external) intercostal membrane
87
Describe the internal intercostal muscle.
The internal intercostal muscle **forms the intermediate** **layer**. Its fibers are **directed downward and backward** **from the subcostal groove** of the rib above to the upper border of the rib below (see Fig. 2.8).
88
The internal intercostal muscle. **extends backward**from the sternum in front to the angles of the ribs behind, where the muscle is **replaced by an aponeurosis,** the \_\_\_\_\_\_\_\_\_\_\_(see Fig. 2.9).
posterior (internal) intercostal membrane
89
Describe the innermost intercostal muscle.
The innermost intercostal muscle **forms the deepest** **layer** and **corresponds to the transversus abdominis muscle** in the **anterior abdominal wall.** It is **an incomplete muscle** **layer** and **crosses more than one intercostal space within** the ribs. It is **related internally to fascia (endothoracic fascia)** and **parietal pleura and externally to the intercostal** **nerves and vessels**. The innermost intercostal muscle can be divided into three portions (see Fig. 2.9), which are more or less separate from one another.
90
What happens when the intercostal muscles contract?
When the intercostal muscles contract, **they all tend to pull the ribs nearer to one another.**
91
What happens during insipiration with the intercostal muscles?
If the **1st rib is fixed by the contraction of the muscles**in the root of the neck, namely, the scaleni muscles, **the intercostal muscles raise the 2nd to the 12th ribs****toward the 1st rib**, as in inspiration.
92
What happens duing expiration with the intercostal muscles?
If, conversely, the **12th rib is fixed by the quadratus** * *lumborum muscle and the oblique muscles of the** * *abdomen**, the **1st to the 11th ribs will be lowered by the** * *contraction of the intercostal muscles, as in expiration.**
93
How does the intercostal muscles help in the intrathoracic pressure?
In addition, the **tone of the intercostal muscles during the different phases of respiration**serves to**strengthen the tissues of the intercostal spaces,**thus**preventing the sucking in or the blowing out of the tissues with changes in intrathoracic pressure.**For further details concerning the action of these muscles, see Mechanics of Respiration on
94
Intercostal Arteries and Veins Each intercostal space contains a
* large ***single posterio***r intercostal artery * and **two small anterior intercostal arteries.**
95
posterior intercostal arteries of the **first two spaces** are branches from?
The **posterior intercostal arteries** of the first two spaces are **branches from the superior intercostal artery**, a ***branch of the costocervical trunk of the subclavian artery.***
96
The ***posterior intercostal arteries of the lower nine spaces***are branches of the :
descending thoracic aorta
97
Th**e anterior intercostal arteries of the lower spaces**are**branches of the\_\_\_\_\_\_\_\_\_\_\_\_**
**musculophrenic artery**, one of the terminal branches of the internal thoracic artery.
98
Each intercostal artery gives off branches to the muscles, skin, and parietal pleura. In the region of the breast in the female, the branches to the superficial structures are particularly large.
99
The **corresponding posterior intercostal veins** drain backward into the __________ (Figs. 2.10 and 2.11),
azygos or hemiazygos veins
100
anterior intercostal veins drain forward into the\_\_\_\_\_\_\_\_\_\_\_\_\_
internal thoracic and the musculophrenic veins.
101
What are the intercostal nerves?
The intercostal nerves are the **anterior rami of the first 11 thoracic spinal nerves** (Fig. 2.12).
102
What is the 12th intercostal nerve?
The **anterior ramus of the 12th thoracic nerve**lies in the**abdomen and runs forward in the abdominal wal**l as the**subcostal nerve.**
103
Describe how the intercostal nerve enters the intercostal space.
Each intercostal nerve **enters an intercostal space between the parietal pleura**and the**posterior intercostal membrane**(see Figs. 2.8 and 2.9). It then runs forward **inferiorly to the intercostal vessels in the subcostal groove of the corresponding rib**,***between the innermost intercostal and internal intercostal muscle.***
104
The **first six nerves** are distributed within their \_\_\_\_\_
intercostal spaces.
105
The 7th to 9th intercostal nerves **leave the anterior ends of their intercostal spaces by passing deep to the costal cartilages, to enter the** \_\_\_\_\_\_\_\_\_\_\_
anterior abdominal wall.
106
The 10th and 11th nerves, since the corresponding ribs are floating, **pass directly into the abdominal wall.**
107
Intercostal nerve branches
* Rami communicantes connect the intercostal nerve to a ganglion of the sympathetic trunk (see Fig. 1.26). The gray ramus joins the nerve medial at the point at which the white ramus leaves it * **collateral branch** runs forward inferiorly to the main nerve on the upper border of the rib below. * **lateral cutaneous branch** runs forward inferiorly to the main nerve on the upper border of the rib below. * **anterior cutaneous branch** * **Muscular branches** run to the intercostal muscles. * **Pleural sensory** branches go to the parietal pleura. * **Peritoneal sensory branche**s (7th to 11th intercostal nerves only) run to the parietal peritoneum
108
The f**irst intercostal nerve** is joined to the \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
brachial plexus by a large branch that is equivalent to the lateral cutaneous branch of typical intercostal nerves The remainder of the first intercostal nerve is small, and there is no anterior cutaneous branch.
109
The **second intercostal nerve** is joined to the **medial cutaneous nerve**of the arm by a branch called the ___________ which is**equivalent to the lateral cutaneous branch of other nerves.**
intercostobrachial nerve,
110
The **2nd intercostal nerve** therefore **supplies the skin of the armpit and the upper medial side of the arm.**
111
With the exceptions noted, the 1st six intercostal nerves therefore supply the skin and the parietal pleura covering the outer and inner surfaces of each intercostal space, respectively, and the intercostal muscles of each intercostal space and the levatores costarum and serratus posterior muscles.
112
In addition, the 7**th to 11th intercostal nerves** supply the
skin and the parietal peritoneum covering the outer and inner surfaces of the abdominal wall, respectively, and the anterior abdominal muscles, which include the external oblique, internal oblique, transversus abdominis, and rectus abdominis muscles.
113
In coronary artery disease, pain is referred along this nerve to the medial side of the arm.
Second intercostal nerve
114
What is a Cervical Rib?
A cervical rib (i.e., a rib arising from the anterior tubercle of the transverse process of the 7th cervical vertebra) occurs in about **0.5% of humans** (Fig. 2.7). It **may have a free anterior end,** may **be connected tbo the 1st rib by a fibrous band,** or **may articulate** **with the 1st rib.** The **importance of a cervical rib is that it** **can cause pressure on the lower trunk** of the **brachial plexus** in some patients, **producing pain down the medial side of the** **forearm and hand and wasting of the small muscles of the hand.** It can also exert pressure on the overlying subclavian artery and interfere with the circulation of the upper limb.
115
What is Rib Excision?
Rib excision is commonly performed by thoracic surgeons wishing to gain entrance to the thoracic cavity. A longitudinal incision is made through the periosteum on the outer surface of the rib, and a segment of the rib is removed. A second longitudinal incision is then made through the bed of the rib, which is the inner covering of periosteum. After the operation, the rib regenerates from the osteogenetic layer of the periosteum
116
Skin Innervation of the Chest Wall and Referred Pain Above the level of the sternal angle, the cutaneous innervation of the anterior chest wall is derived from the supraclavicular nerves (C3 and 4). Below this level, the anterior and lateral cutaneous branches of the intercostal nerves supply oblique bands of skin in regular sequence. The skin on the posterior surface of the chest wall is supplied by the posterior rami of the spinal nerves. The arrangement of the dermatomes is shown in Figures 1.23 and 1.24.
117
An intercostal nerve not only supplies areas of skin, but also supplies the ribs, costal cartilages, intercostal muscles, and parietal pleura lining the intercostal space. Furthermore, the 7th to 11th intercostal nerves leave the thoracic wall and enter the anterior abdominal wall so that they, in addition, supply dermatomes on the anterior abdominal wall, muscles of the anterior abdominal wall, and parietal peritoneum. This latter fact is of great clinical importance because it means that disease in the thoracic wall may be revealed as pain in a dermatome that extends across the costal margin into the anterior abdominal wall. For example, a pulmonary thromboembolism or a pneumonia with pleurisy involving the costal parietal pleura could give rise to abdominal pain and tenderness and rigidity of the abdominal musculature. The abdominal pain in these instances is called **referred pain.**
118
Herpes zoster, or shingles, is a relatively common condition caused by the reactivation of the latent varicella-zoster virus in a patient who has previously had chickenpox. The lesion is seen as an inflammation and degeneration of the sensory neuron in a cranial or spinal nerve with the formation of vesicles with inflammation of the skin. In the thorax, the **first symptom is a band of dermatomal pain in the distribution of the sensory neuron in a thoracic spinal nerve,** followed in a few days by a skin eruption. The condition occurs most frequently in patients older than 50 years.
119
Describe the suprapleural membrane.
Superiorly, the **thorax opens into the root of the neck** by a **narrow aperture, the thoracic outlet** (see page 39). The outlet transmits structures that pass between the thorax and the neck (esophagus, trachea, blood vessels, etc.) and for the most part lie close to the midline. On either side of these structures, the **outlet is closed by a dense fascial** **layer called the suprapleural membrane** (Fig. 2.13). This **tent-shaped fibrous sheet is attached laterally to the medial** **border of the 1st rib and costal cartilage****.** It is attached at its apex to the tip of the transverse process of the seventh cervical vertebra and medially to the fascia investing the structures passing from the thorax into the neck. ***It protects*** ***the underlying cervical pleura and resists the changes in intrathoracic pressure occurring during respiratory movements.***
120
Thoracic Cage Distortion The shape of the thorax can be distorted by **:**
**congenital anomalies of the vertebral column or by the ribs**. Destructive disease of the vertebral column that produces lateral flexion or scoliosis results in marked distortion of the thoracic cage.
121
What is the endothoracic fascia?
The endothoracic fascia is a thin layer of loose connective tissue that separates the parietal pleura from the thoracic wall. The suprapleural membrane is a thickening of this fascia.
122
Describe the diagphragm.
The **diaphragm** is a **thin muscular and tendinous septum** that **separates the chest cavity above from the abdominal cavity below** (Fig. 2.16). It is pierced by the structures that pass between the chest and the abdomen. It is **dome shaped and consists of a peripheral muscular part**, which arises from the margins of the thoracic opening, and a centrally placed tendon (
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The origin of the diaphragm can be divided into three parts:
* sternal part * costal part * vertebral part
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Where does the sternal part of the diagphram arises?
A sternal part arising from the **posterior surface of the xiphoid process**
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Where does the costal part of the diaphram arises?
A costal part arising from the **deep surfaces of the lower six ribs and their costal cartilages**
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Where does the vertebral part of the diagphram arises?
A **vertebral part** arising by vertical columns or crura and **from the arcuate ligaments**
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Where does the right crus of the diaphragm arises?
The right crus arises from the **sides of the bodies of the first** **three lumbar vertebrae** and the **intervertebral discs.**
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Where does the left crus arises?
the left crus arises **from the sides of the bodies of the first two lumbar** **vertebrae and the intervertebral disc**
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Lateral to the **crura the diaphragm arises from the :**
**medial and lateral arcuate ligaments**
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The medial arcuate ligament extends from the side of the body of the second lumbar vertebra to the tip of the transverse process of the first lumbar vertebra. The lateral arcuate ligament extends from the tip of the transverse process of the first lumbar vertebra to the lower border of the 12th rib.
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The lateral arcuate ligament extends from the **tip of the transverse process of the first lumbar vertebra**to the**lower border of the 12th rib.**
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The medial borders of the two crura are connected by a \_\_\_\_\_\_\_\_, which crosses over the anterior surface of the aorta
median arcuate ligament
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The diaphragm is inserted into a **\_\_\_\_\_\_-** which is **shaped like three leaves.**
**central tendon** The superior surface of the tendon is partially fused with the inferior surface of the fibrous pericardium. **Some of the muscle fibers of the right crus pass up to the left and surround the esophageal orifice in a slinglike loop.** **These fibers appear to act as a *sphincter and possibly assist in the prevention of regurgitation*of the stomach contents into the thoracic part of the esophagus**
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Traumatic Injury to the Thorax Traumatic injury to the thorax is common, especially as a result of automobile accidents.
* Fractured Sternum * Rib Contusion * Rib Fractures * Flail Chest
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Traumatic Injury to the Thorax What is the reason that fracture to the sternum is not common?
The sternum is a **resilient structure that is held in position** by **relatively pliable costal cartilage**s and **bendable ribs.** however, it does occur in **high-speed motor vehicle accidents.** ***Remember that the heart lies posterior to the sternum and may be severely contused by the sternum on impact.***
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Traumatic Injury to the Thorax What is the most common rib injury?
Rib Contusion **Bruising of a rib, secondary to trauma,** is the most common rib injury. In this painful condition, a small hemorrhage occurs beneath the periosteum.
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Traumatic Injury to the Thorax What is the common chest injuries?
Fractures of the ribs are common chest injuries.
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Why is rib fracture in children rare?
In children, **the ribs are highly elastic**, and fractures in this age group are therefore rare. Unfortunately, the pliable chest wall in the young can be easily compressed so that the underlying lungs and heart may be injured. With increasing age, the rib cage becomes more rigid, owing to the deposit of calcium in the costal cartilages, and the ribs become brittle.
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The ribs then tend to break at their weakest part, their \_\_\_\_\_\_\_\_\_.
angles
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What ribs are prone to fracture?
The ribs prone to fracture are **those that are exposed or relatively** **fixed**. Ribs **5 through 10 are the most commonly fractured** ribs. The ***first four ribs are protected by the clavicle and pectoral*** ***muscles anteriorly and by the scapula and its associated muscles*** ***posteriorly.*** The 11th and 12th ribs float and move with the force of impact.
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Because the rib is sandwiched between the skin externally and the delicate pleura internally, it is not surprising that the **jagged ends of a fractured rib may penetrate the lungs and present as a pneumothorax.**
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What is the most important symptom of a fractureed rib?
Severe localized pain is usually the most important symptom of a fractured rib. The periosteum of each rib is innervated by the intercostal nerves above and below the rib. To encourage the patient to breathe adequately, it may be necessary to relieve the pain by performing an intercostal nerve block.
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What is a flail chest?
In severe crush injuries, a number of ribs may break. If limited to one side, the fractures may occur near the rib angles and anteriorly near the costochondral junctions. This causes flail chest, in which a section of the chest wall is disconnected to the rest of the thoracic wall. If the fractures occur on either side of the sternum, the sternum may be flail. In either case, the stability of the chest wall is lost, and the flail segment is sucked in during inspiration and driven out during expiration, producing **paradoxical and ineffective respiratory movements**
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Traumatic Injury to the Back of the Chest The posterior wall of the chest in the midline is formed by the vertebral column. In severe posterior chest injuries, the possibility of a vertebral fracture with associated injury to the spinal cord should be considered. Remember also the presence of the scapula, which overlies the upper seven ribs. This bone is covered with muscles and is fractured only in cases of severe trauma.
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Traumatic Injury to the Abdominal Viscera and the Chest
When the anatomy of the thorax is reviewed, it is important to remember that the upper abdominal organs—namely, the liver, stomach, and spleen—may be injured by trauma to the rib cage. In fact, any injury to the chest below the level of the nipple line may involve abdominal organs as well as chest organs
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Describe the shape of the Diaphragm.
Shape of the Diaphragm As seen from in front, the **diaphragm curves up into right and left domes, or cupulae.**
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The right dome of the diaphragm reaches as high as the **upper borde**r of what rib?
5th rib,
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and the left dome of the diaphragm may reach the lower border of the\_\_\_\_\_\_\_ rib.
5th
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What is the reason behind why the right dome of the diaphragm lies higher than the left?
(The right dome lies at a higher level, because of the **large size of the right lobe of the liver.)**
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Where does the central tendon of the diaphragm lies?
The central tendon lies at the level of the **xiphisternal joint.** The **domes support the right and left lungs,** whereas the **central tendon supports the heart.**
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The levels of the diaphragm vary with the **:**
* **phase of respiration,** * the **posture,** * and the **degree of distention of the abdominal viscera.**
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How is the diaphragm when a person is sitting or standing?
The **diaphragm is lower when a person is sitting or standing**
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What position is the diaphragm higher?
; it is higher in the **supine position and after a large meal**.
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What is the appearance of the diaphragm when its from the side?
When seen from the side, the diaphragm has the appearance of an **inverted J,** the **long limb extending up from the** **vertebral column and the short limb extending forward to** **the xiphoid process** (see Fig. 2.2).
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Nerve Supply of the Diaphragm Motor nerve supply
The right and left phrenic nerves | (C3, 4, 5)
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Nerve Supply of the Diaphragm Sensory nerve supply
The parietal pleura and peritoneum covering the central surfaces of the diaphragm are from the **phrenic nerve and the periphery of the diaphragm** is from the **lower six intercostal nerves**
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What is the action of the Diaphragm?
On contraction, the **diaphragm pulls down its central tendon** and **increases the vertical diameter of the thorax.**
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Functions of the Diaphragm
* Muscle of inspiration * Muscle of abdominal straining * Weight-lifting muscle * Thoracoabdominal pump:
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Discuss diaphragm as a muscle of inspiration.
Muscle of inspiration: **On contraction**, the **diaphragm pulls its central tendon down**and**increases the vertical diameter of the thorax**. The **diaphragm is the most important muscle used in inspiration.**
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Describe the diaphragm as a muscle of abdomina straining.
Muscle of abdominal straining: The contraction of the diaphragm **assists the contraction of the muscles** of the **anterior abdominal wall** in raising the intra-abdominal pressure for **micturition, defecation, and parturition.** This mechanism is further aided by the **person taking** **a deep breath and closing the glottis of the larynx.** The diaphragm is **unable to rise because of the air trapped** **in the respiratory tract.** Now and again, **air is allowed to** **escape, producing a grunting sound.**
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Discuss Diaphragm as a Weight- ligting muscle.
Weight-lifting muscle: In a person taking a deep breath and holding it (fixing the diaphragm), the diaphragm **assists the muscles of the anterior abdominal wall in raising the intra-abdominal pressure to such an extent that it helps support the vertebral column and prevent flexion**. This **greatly assists the postvertebral muscles in the lifting of heavy weights**. Needless to say, it is important to have **adequate sphincteric control of the bladder and anal canal under these circumstances**
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Discuss the Diaphragm as a Thoracoabdomina pump.
Thoracoabdominal pump: The descent of the diaphragm * *decreases the intrathoracic pressure** and at the * *same time increases the intra-abdominal pressure.** This pressure change **compresses the blood in the inferior** **vena cava** and **forces it upward into the right atrium of** the heart. Lymph within the abdominal lymph vessels is also **compressed, and its passage upward within the thoracic duct**is**aided by the negative intrathoracic pressure.** The presence of valves within the thoracic duct prevents backflow.
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Explain how is Thoracotomy done?
Thoracotomy In patients with penetrating chest wounds with uncontrolled intrathoracic hemorrhage, thoracotomy may be a life-saving procedure. After preparing the skin in the usual way, the **physician makes an incision over the fourth or fifth intercostal** **space,** extending from the **lateral margin of the sternum to** **the anterior axillary line** (Fig. 2.15). Whether to make a right or left incision depends on the site of the injury. For access to the heart and the aorta, the chest should be entered from the left side.
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The following tissues will be incised in thoracotomy (see Fig. 2.14):
(a) skin, (b) subcutaneous tissue, (c) serratus anterior and pectoral muscles, (d) external intercostal muscle and anterior intercostal membrane, (e) internal intercostal muscle, (f) innermost intercostal muscle, (g) endothoracic fascia, and (h) parietal pleura.
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What is to be avoided in internal thoracic artery?
Avoid the internal thoracic artery, which r**uns vertically downward behind the costal cartilages**about a**fingerbreadth lateral to the margin of the sternum**, and the i**ntercostal vessels and nerve,**which**extend forward in the subcostal groove** in the upper part of the intercostal space (see Fig. 2.14).
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What is a hiccup?
Hiccup is the **involuntary spasmodic contraction** of the **diaphragm** **accompanied by the approximation of the vocal folds** and **closure of the glottis of the larynx** . It is a **common condition in normal individuals** and **occurs after eating or drinking as a result of gastric irritation of the vagus nerve endings**. ***It may, however, be a symptom of disease such as pleurisy, peritonitis, pericarditis, or uremia.***
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How can the Paralysis of the Diaphragm occur?
A single dome of the diaphragm may be paralyzed **by crushing** **or sectioning of the phrenic nerve in the neck**. This may be necessary in the **treatment of certain forms of lung tuberculosis,** **when the physician wishes to rest the lower lobe of the lung** **on one side.** Occasionally, the contribution from the fifth cervical spinal nerve joins the phrenic nerve late as a branch from the nerve to the subclavius muscle. This is known as the accessory phrenic nerve. To obtain complete paralysis under these circumstances, the nerve to the subclavius muscle must also be sectioned.
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Openings in the Diaphragm The diaphragm has three main openings:
* aortic opening * esophageal opening * caval opening **ACE**
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Where does the aortic opening lies?
The aortic opening lies **anterior to the body of the 12th** **thoracic vertebra** between the crura (see Fig. 2.16).
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Aortic opening transmits what?
It transmits the: * **aorta,** * the **thoracic duct,** * and the **azygos vein.**
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Where does the esophageal opening lies?
The esophageal opening lies at the **level of the 10th thoracic** **vertebra** in a sling of muscle fibers derived from the right crus (see Fig. 2.16).
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What does the esophageal opening transmits?
It transmits the **esophagus,** the * *right and left vagus nerves**, the **esophageal branches of** * *the left gastric vessels,** and the **lymphatics from the lower** **third of the esophagus.**
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Where does the caval opening lies?
The caval opening lies at the level of the **8th thoracic** **vertebra in the central tendon** (see Fig. 2.16). Ceight!! ( KATE)
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What does the caval opening transmits?
It transmits the **inferior vena cava and terminal branches of the** **right phrenic nerve.**
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So the arrangement of the opening on the diaphragm maybe as follows:
CEA * Caval opening * Esophageal * Aorta
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In addition to the openings of the diaphragm what else can pierce the diaphragm?
* In addition to these openings, the **sympathetic splanchnic nerves** pierce the crura; the sympathetic trunks **pass posterior to the medial arcuate ligament on each side;** * and the **superior epigastric vessel**s pass between the sternal and costal origins of the diaphragm on each side (see Fig. 2.16).
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What does the Internal Thoracic Artery supplies?
The internal thoracic artery **supplies the anterior wall of the** **body from the clavicle to the umbilicus.**
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The internal thoracic artery is a branch of the ?
It is a branch of the **first part of the subclavian artery in the neck.** It descends vertically on the pleura behind the costal cartilages, a fingerbreadth lateral to the sternum, and ends in the sixth intercostal space by dividing into the superior epigastric and musculophrenic arteries (see Figs. 2.9 and 2.1
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What are the branches of the Internal Thoracic Artery?
Branches: ■■ **Two anterior intercostal arteries** for the upper six intercostal spaces ■■ **Perforating arteries**, which accompany the terminal branches of the corresponding intercostal nerves ■■ The **pericardiacophrenic artery**, which accompanies the phrenic nerve and supplies the pericardium ■■ **Mediastinal arteries** to the contents of the anterior mediastinum (e.g., the thymus) ■■ The **superior epigastric artery,** which enters the rectus sheath of the anterior abdominal wall and supplies the rectus muscle as far as the umbilicus ■■ The **musculophrenic artery**, which runs around the costal margin of the diaphragm and supplies the lower intercostal spaces and the diaphragm
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Where does the Internal Thoracic Vein drain?
The internal thoracic vein accompanies the internal thoracic artery and drains into the **brachiocephalic vein on** **each side.**
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Describe the Levatores Costarum.
Levatores Costarum There are 12 pairs of muscles . Each levator costa is **triangular** **in shape** and **arises by its apex from the tip of the transverse** **process** and is inserted into the rib below.
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What is the action of Levatores Costarum?
■■ Action: Each **raises the rib below and is therefore an inspiratory muscle.**
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What is the nerve supply of the Levatores Costarum?
■■ Nerve supply: **Posterior rami of thoracic spinal nerve**s.
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Describe the Serratus **Posterior Superior** Muscle
The serratus posterior superior is a **thin, flat muscle** that **arises from the lower cervical and upper thoracic spines.** Its fibers pass downward and laterally and are inserted into the upper ribs.
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What is the action of Serratus Posterior Superior Muscle?
■■ Action: It **elevates the ribs and is therefore an inspiratory** **muscle.**
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What is the nerve supply of Serratus Posterior Superior Muscle?
■■ Nerve supply: Intercostal nerves.
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What is the **Serratus Posterior Inferior** MM?
Serratus Posterior Inferior Muscle The serratus posterior inferior is a **thin, flat muscle** that **arises from the upper lumbar and lower thoracic spines.** Its fibers **pass upward and laterally and are inserted into the lower ribs**
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What is the Serratus Posterior Inferior muscle action?
■■ Action: It depresses the ribs and is therefore an expiratory muscle.
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What is the Serratus Posterior Inferior nerve supply?
■■ Nerve supply: Intercostal nerves
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FIGURE 2.15 Left thoracotomy . A. Site of skin incision over fourth or fifth intercostal space . B. The exposed ribs and associated muscles. The line of incision through the intercostal space should be placed close to the upper border of the rib to avoid injuring the intercostal vessels and nerve. C. The pleural space opened and the left side of the mediastinum exposed. The left phrenic nerve descends over the pericardium beneath the mediastinal pleura. The collapsed left lung must be pushed out of the way to visualize the mediastinum
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FIGURE 2.16 Diaphragm as seen from below. The anterior portion of the right side has been removed. Note the sternal, costal, and vertebral origins of the muscle and the important structures that pass through it.
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What are your inspiratory muscles?
* Serratus posterior superior * Levatores costarum (12)
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