Session 1.2c - Gray's Anatomy For Students - Thorax - Regional anatomy - Thoracic wall Flashcards
https://www.clinicalkey.com/#!/content/book/3-s2.0-B9780702051319000031?scrollTo=%23hl0001490 (286 cards)
1
Q
How does the thoracic wall appear?
A
Segmental in design
2
Q
What is the thoracic wall composed of?
A
Skeletal elements and muscles
3
Q
Where is the thoracic wall bound to superiorly?
A
The superior thoracic aperture, bordered by vertebra TI, rib I, and the manubrium of the sternum
4
Q
Where is the thoracic wall bound to inferiorly?
A
The inferior thoracic aperture, bordered by vertebra TXII, rib XII, the end of rib XI, the costal margin, and the xiphoid process of the sternum.
5
Q
What are the skeletal elements of the thoracic wall?
A
The skeletal framework consists of the thoracic vertebrae, intervertebral discs, ribs and sternum
6
Q
How many thoracic vertebrae are there?
A
Twelve THORACIC VERTEBRAE.
7
Q
How are the 12 thoracic vertebrae characterised?
A
By articulations with ribs.
8
Q
What is the shape of the body of a typical thoracic vertebra?
A
A typical thoracic vertebra has a heart-shaped VERTEBRAL BODY.
9
Q
Describe the dimensions of the body of a typical thoracic vertebra.
A
Roughly equal dimensions in the transverse and anteroposterior directions (Fig. 3.18)
10
Q
Describe the spinous process of a typical thoracic vertebra.
A
Long spinous processes (Fig. 3.18)
11
Q
How do the vertebral foramen of the typical thoracic vertebra appear?
A
The VERTEBRAL FORAMEN is generally circular
12
Q
How are the lamina of the vertebra?
A
The LAMINAE are broad and overlap with those of the vertebra below.
13
Q
Describe the superior articular processes of a typical thoracic vertebra.
A
The SUPERIOR ARTICULAR PROCESSES are flat, with their articular surfaces facing almost directly posteriorly.
14
Q
Describe the inferior articular processes of a typical thoracic vertebra.
A
The INFERIOR ARTICULAR PROCESSES project from the laminae and their articular facets face anteriorly.
15
Q
Describe the transverse processes of a typical thoracic vertebra.
A
The TRANSVERSE PROCESSES are club shaped and project posterolaterally.
16
Q
How do the vertebra articulate with the ribs?
A
A typical thoracic vertebra has three sites on each side for articulation with ribs.
17
Q
What are demifacets?
A
i.e. partial facets
18
Q
Where are the demifacets located?
A
On the superior and inferior aspects of the body
19
Q
What do the demifacets articulate with?
A
Corresponding sites on the heads of adjacent ribs.
20
Q
What does the superior facet articulate with?
A
The SUPERIOR COSTAL FACET articulates with part of the head of its own rib
21
Q
What does the inferior costal facet articulate with?
A
The INFERIOR COSTAL FACET articulates with part of the head of the rib below.
22
Q
What is the oval facet on the thoracic vertebra called?
A
TRANSVERSE COSTAL FACET
23
Q
What shape is the transverse costal facet?
A
Oval
24
Q
Where is the transverse costal facet?
A
At the end of the transverse process
25
What does the transverse costal facet articulate with?
The tubercle of its own rib
26
Not all vertebra articulate with ribs in a typical fashion. Which ones?
TI, TX, TXI and TXII (Fig. 3.19)
27
Describe the rib articulation of TI.
The superior costal facets on the body of vertebra TI are complete and articulate with a single facet on the head of its own rib - in other words, the head of rib I does not articulate with vertebra CVII.
28
Describe the rib articulation of TX.
Similar to TI, TX (and often TIX) articulates only with its own ribs and therefore lacks inferior demifacets on the body.
29
Describe the rib articulation of TXI and TXII.
These articulate only with the heads of their own ribs - they lack transverse costal facets and have only a single complete facet on each side of their bodies.
30
Which vertebra only articulate with their own ribs?
TI, TX (and often TIX), TXI and TXII.
31
Some vertebra only articulate with their own ribs. What is different about the costal facets of these?
TI - superior costal facet complete
(TIX) TX - lacks inferior demifacets
TXI and TXII - lack transverse costal facets and have a single complete facet on each side of their bodies
32
How many ribs are there?
Twelve pairs of ribs
33
What does each rib terminate as?
They terminate anteriorly in a costal cartilage (Fig. 3.20).
34
What do all ribs articulate with?
The vertebral column
35
What articulates with the sternum?
The costal cartilages of the upper seven ribs
36
Which are the true ribs?
The upper seven ribs
37
Ribs I-VII are known as what, and articulate with what?
TRUE RIBS, articulate directly with the sternum
38
What are ribs VIII-XII known as?
The remaining five pairs of ribs are FALSE RIBS
39
How many true and false ribs are there?
7 true, 5 false
40
What do ribs VIII to X articulate with?
The costal cartilages articulate anteriorly with the costal cartilages of the ribs above.
41
What do ribs XI and XII articulate with?
These have no anterior connection with other ribs or with the sternum
42
What are ribs XI and XII often known as?
FLOATING RIBS
43
Which ribs are the floating ribs?
Ribs XI and XII
44
What does a typical rib consist of?
A curved shaft with anterior and posterior ends (Fig. 3.21).
45
What is the anterior end of the rib continuous with?
Its costal cartilage
46
What does the posterior end of the rib articulate with?
The vertebral column
47
How is the posterior end of the rib characterised?
By a head, neck and tubercle.
48
Describe the head of the rib.
The HEAD is somewhat expanded and typically presents two articular surfaces.
49
What are the two articular surfaces on the head separated by?
The HEAD presents two articular surfaces separated by a CREST.
50
Describe the relative sizes of the two articular surfaces of the head.
The superior surface is smaller than the larger inferior facet.
51
What does the superior surface on the head of the rib articulate with?
The inferior costal facet on the body of the vertebra above
52
What does the inferior surface (facet) on the head of the rib articulate with?
The superior costal facet of its own vertebra.
53
Describe the neck of the rib.
The NECK is a short flat region of bone that separates the head from the tubercle.
54
Describe the tubercle of the rib.
The TUBERCLE projects posteriorly from the junction of the neck with the shaft and cosistd of two regions, an articular part and a nonarticular part.
55
Describe the articular part of the tubercle of the rib.
The articular part is medial and has an oval facet for articulation with a corresponding facet on the transverse process of the associated vertebra.
56
Describe the nonarticular part of the tubercle of the rib.
The raises nonarticular part is roughened by ligament attachments.
57
Describe the shaft of the rib.
Generally thin and flat with internal and external surfaces.
58
Describe the superior margin of the rib.
Smooth and rounded
59
Describe the inferior margin of the rib.
Sharp
60
What is the relationship of the shaft to the tubercle?
The shaft bends forward just laterally to the tubercle at a site termed the ANGLE.
61
Where does the shaft face, and how?
It has a gentle twist around its longitudinal axis so that the external surface of the anterior part of the shaft faces somewhat superiorly relative to the posterior part.
62
How is the inferior margin of the internal surface marked?
By a distinct COSTAL GROOVE.
63
Which ribs have distinct features?
Upper and lower ribs
| - Rib I, II, X, XI and XII (Fig. 3.22)
64
Describe the orientation of rib I.
RIB I is flat in the horizontal plane.
65
Describe the superior and inferior surfaces of rib I.
They are broad.
66
Describe the orientation of rib I from its articulation with vertebra TI.
It slopes inferiorly to its attachment to the manubrium of the sternum.
67
Describe the head of rib I.
The head articulates only with the body of vertebra TI and therefore has only one articular surface.
68
Describe the tubercle of rib I.
Like other ribs, the tubercle has a facet for articulation with the transverse process.
69
Describe the superior surface of rib I.
It is characterised by a distinct tubercle, the SCALENE TUBERCLE.
70
What does the scalene tubercle do?
Separates two smooth grooves that cross the rib approximately midway along the shaft.
71
What runs along the anterior groove of rib I?
The subclavian vein
72
What runs along the posterior groove of rib I?
The subclavian artery
73
Anterior and posterior to the grooves by the scalene tubercle (rib I), how does the shaft appear?
It is roughened by muscle and ligament attachments.
74
Describe rib II.
RIB II, like rib I, is flat but twice as long.
75
What does rib II articulate with?
The vertebral column in a way typical of most ribs.
76
Describe the head of rib X.
The head of RIB X has a single facet for articulation with its own vertebra.
77
Describe the structure and function of ribs XI and XII.
RIBS XI and XII articulate only with the bodies of their own vertebrae and have no tubercles or necks.
78
Describe the appearance of ribs XI and XII.
Both ribs are short, have little curve, and are pointed anteriorly.
79
What does the adult sternum consist of?
```
The adult STERNUM consists of three major elements:
- manubrium
- body
- xiphoid process
(Fig. 3.23)
```
80
Describe the manubrium of the sternum.
Broad and superiorly positioned (Fig. 3.23)
81
Describe the body of the sternum.
Narrow and longitudinally oriented (Fig. 3.23)
82
Describe the xiphoid process of the sternum.
Small and inferiorly positioned (Fig. 3.23)
83
What does the manubrium of the sternum form?
Part of the bony framework of the neck and the htorax.
84
What occurs on the superior surface of the manubrium?
It is expanded laterally
85
What is found on the superior surface of the manubrium?
A distinct and palpable notch: the JUGULAR NOTCH (SUPRASTERNAL NOTCH), in the midline.
86
What is found either side of the jugular notch?
A large oval fossa for articulation with the clavicle.
87
What is found immediately inferior to the fossa, either side of the jugular notch?
Immediately inferior, on each lateral surface of the manubrium, is a facet for the attachment of the first costal cartilage.
88
What is found at the lower end of the lateral border of the facet that attaches to the first costal cartilage?
A demifacet for articulation with the upper half of the anterior end of the second costal cartilage.
89
Describe the body of the sternum.
It is flat.
90
What is the anterior surface of the body of the sternum marked by?
Often marked by transverse ridges
91
What do the transverse ridges on the body of the sternum represent?
Lines of fusion between the segmental elements called sternebrae
92
Where does the body of the sternum arise embryologically?
From the sternebrae (transverse ridges on sternum)
93
What is found on the lateral margins of the body of the sternum?
Articular facets for costal cartilages.
94
What does the body of the sternum have superiorly?
Each lateral margin has a demifacet for articulation with the inferior aspect of the second costal cartilage.
95
How many facets are there on the body of the sternum, inferior to the first demifacet?
Four facets
96
What do the facets of the body of the sternum articulate with?
The costal cartilages of ribs III to VI.
97
What is found at the inferior end of the body of the sternum?
A demifacet for articulation with the upper demifacet on the seventh costal cartilage.
98
What is the inferior end of the body of the sternum attached to?
The xiphoid process.
99
Which is the smallest part of the sternum?
The XIPHOID PROCESS.
100
Describe the shape of the xiphoid process.
Its shape is variable: it may be wide, thin, pointed, bifid, curved or perforated.
101
How does the xiphoid process begin and mature.
It begins as a cartilaginous structure, which becomes ossified in the adult.
102
What is found on the upper lateral margin of the xiphoid process, on each side?
A demifacet for articulation with the inferior end of the seventh costal cartilage.
103
What does a typical rib articulate with?
The bodies of adjacent vertebrae and the transverse process of its related vertebra.
104
What do the bodies of adjacent vertebrae articulate wth on the rib?
They form a joint with the head of the rib
105
What is the joint between a typical rib and the transverse process of its related vertebra known as?
A COSTOTRANSVERSE JOINT (Fig. 3.24)
106
What do the costovertebral joints and related ligaments do?
They allow the necks of the ribs either to rotate around their longitudinal axes, or to ascend and descend relative to the vertebral column.
107
Where do the costovertebral joints allow the necks of the ribs to rotate around their longitudinal axes?
Mainly in the upper ribs
108
Where do the costovertebral joints allow the necks of the ribs to ascend and descend relative to the vertebral column?
Mainly in the lower ribs.
109
How do the ribs aid breathing?
The combined movement of all of the ribs on the vertebral column are essential for altering the volume of the thoracic cavity during breathing.
110
What do the two facets on the head of the rib articulate with?
The superior facet on the body of its own vertebra and the inferior facet on the body of the vertebra above.
111
How is the joint between the head of the rib and the vertebra divided?
Into two synovial compartments by an intra-articular ligament
112
How does the intra-articular ligament of the rib/vertebral joint occur?
It attaches the crest to the adjacent intervertebral disc and separates the two articular surfaces on the head of the rib.
113
What are the two synovial compartments and the intervening ligament surrounded by?
A single joint capsule
114
What is the joint capsule around the two synovial compartments and intra-articular ligament of the rib attached to?
The outer margins of the combined articular surfaces of the head and vertebral column.
115
What type of joints are costotransverse joints?
Synovial joints
116
Where are costotransverse joints found?
Between the tubercle of a rib and the transverse process of the related vertebra (Fig. 3.24).
117
Describe the capsule related to the costotransverse joint.
The capsule surrounding each joint is thin.
118
How is the costotransverse joint stabilised?
By two strong extracapsular ligaments
- COSTOTRANSVERSE LIGAMENT
- LATERAL COSTOTRANSVERSE LIGAMENT
119
Where are the extracapsular ligaments that stabilise the joint capsule on the costotransverse joints?
They span the space between the transverse process and the rib on the medial and lateral sides of the joint
120
Where is the costotransverse ligament?
It is medial to the joint and attaches the neck of the rib to the transverse process.
121
Where is the lateral costotransverse ligament?
Lateral to the joiunt and attaches the tip of the transverse process to the roughened nonarticular part of the tubercle of the rib.
122
What and where is the superior costotransverse ligament?
This is a third ligament, which attaches the superior surface of the neck of the rib to the transverse process of the vertebra above.
123
What movements occur at costotransverse joints?
Slight gliding movement
124
Where are the sternocostal joints?
Between the upper seven costal cartilages and the sternum (Fig. 3.25)
125
What type of joint is the joint between rib I and the manubrium?
It is not synovial and consists of a fibrocartilaginous connection between the manubrium and the costal cartilage.
126
What type of joint is the second to seventh sternocostal joints?
Synovial
127
What do the second to seventh sternocostal joints have to reinforce it?
Thin capsules reinforced by surrounding sternocostal ligaments.
128
How is the joint between the second costal cartilage and the sternum divided?
Into two compartments, by an intraarticular ligament.
129
What does the intraarticular ligament do?
Attaches the second costal cartilage to the junction of the manubrium and the body of the sternum.
130
Where do interchondral joints occur?
Between the costal cartilages of adjacent ribs (Fig. 3.25)
131
Which costal cartilages do interchondral joints mainly occur between?
Ribs VII to X, but may also involve the costal cartilages of ribs V and VI.
132
What is the function of interchondral joints?
- Provide indirect anchorage to the sternum
| - Contribute to the formation of a smooth inferior costal margin
133
What is the structure of interchondral joints?
They are usually synovial, and the thin fibrous capsules are reinforced by interchondral ligaments.
134
What is the joint between the manubrium and the body of the sternum?
Usually symphyses (Fig. 3.25)
135
What is the joint between the body of the sternum and the xiphoid process?
Usually symphyses (Fig. 3.25)
136
What movements occur between the manubrium and the body of the sternum during respiration?
Only slight angular movements.
137
What occurs between the body of the sternum and the xiphoid process with age?
The joint often becomes ossified
138
What is a clinically useful feature of the manubriosternal joint?
It can be palpated easily
139
Why can the manubriosternal joint be palpated easily?
Because the manubrium normally angles posteriorly on the body of the sternum.
140
What does the manubriosternal joint produce?
A raised feature referred to as the sternal angle.
141
What does the sternal angle mark?
This elevation marks the site of articulation of rib II with the sternum.
142
Why is rib I not used in palpation?
Rib I is not palpable, because it lies inferior to the clavicle and is embedded in tissues at the based of the neck.
143
How do you palpate/count ribs?
Rib II is used as a reference for ocunting ribs and can be felt immediately lateral to the sternal angle.
144
How is the sternal angle related to the vertebral column?
It lies on a horizontal plane that passes through the intervertebral disc between vertebrae TIV and TV (Fig. 3.10).
145
Where does the superior mediastinum separate from the inferior mediastinum?
Horizontal plane that passes through the intervertebral disc between vertebrae TIV and TV.
146
Where is the superior border of the pericardium found?
Horizontal plane that passes through the intervertebral disc between vertebrae TIV and TV.
147
What does the horizontal plane that passes through the intervertebral disc between vertebrae TIV and TV mark?
- Sternal angle
- Superior/inferior mediastinum separation
- Superior border of the pericardium
- End of the ascending aorta
- Beginning and end of the arch of aorta
- Beginning of the thoracic aorta
- Bifurcation of the trachea (just superior to the pulmonary trunk)
Fig. 3.79 and 3.86
148
Describe the intercostal spaces.
They lie between adjacent ribs and are filled by intercostal muscles (Fig. 3.26).
149
Where precisely do intercostal nerves and associated major arteries and veins lie?
In the COSTAL GROOVE along the inferior margins of the superior rib and pass in the plane between the inner two layers of muscles.
150
In each space, which structure is most superior?
The vein, and is therefore highest in the costal groove.
151
Which structure is immediately inferior to the vein in the intercostal space?
Artery
152
Which structure is immediately inferior to the artery in the intercostal space?
The nerve, and as the most inferior, is often not protected by the groove.
153
Which structure is most at risk when objects perforate the upper aspect of an intercostal space?
The nerve, as it is the most inferior (out of the intercostal nerve, artery and vein) and often not protected by the groove.
154
Small collateral branches of the major intercostal nerves and vessels are often present where?
Superior to the inferior rib below.
155
What is found deep to the intercostal spaces and ribs?
ENDOTHORACIC FASCIA
156
What does endothoracic fascia do?
It separates the intercostal spaces and ribs from the underlying pleura.
157
What is the endothoracic fascia?
A layer of loose connective tissue, which contains variable amounts of fat.
158
What is found superficial to the intercostal spaces?
Deep fascia, superficial fascia and skin.
159
What overlies the intercostal spaces?
Muscles associated with the upper limbs and back.
160
What do muscles of the thoracic wall include?
Those that:
- fill and support the intercostal spaces
- pass between the sternum and ribs
- cross several ribs between costal attachments
(Table 3.2 - Muscles of the thoracic wall)
161
(Table 3.2: Muscles of the thoracic wall)
What is the superior attachment of the external intercostal muscles?
Inferior margin of rib above
162
(Table 3.2: Muscles of the thoracic wall)
What is the inferior attachment of the external intercostal muscles?
Superior margin of rib below
163
(Table 3.2: Muscles of the thoracic wall)
What is the innervation of the external intercostal muscles?
Intercostal nerves; T1-T11
164
(Table 3.2: Muscles of the thoracic wall)
What is the function of the external intercostal muscles?
Most active during inspiration; supports intercostal space; moves ribs superiorly
165
(Table 3.2: Muscles of the thoracic wall)
What is the superior attachment of the internal intercostal muscles?
Lateral edge of costal groove of rib above
166
(Table 3.2: Muscles of the thoracic wall)
What is the inferior attachment of the internal intercostal muscles?
Superior margin of rib below deep to the attachment of the related external intercostal
167
(Table 3.2: Muscles of the thoracic wall)
What is the innervation of the internal intercostal muscles?
Intercostal nerves; T1-T11
168
(Table 3.2: Muscles of the thoracic wall)
What is the function of the internal intercostal muscles?
Most active during expiration; supports intercostal space; moves ribs inferiorly
169
(Table 3.2: Muscles of the thoracic wall)
What is the superior attachment of the innermost intercostal muscles?
Medial edge of costal groove of rib above
170
(Table 3.2: Muscles of the thoracic wall)
What is the inferior attachment of the innermost intercostal muscles?
Internal aspect of superior margin of rib below
171
(Table 3.2: Muscles of the thoracic wall)
What is the innervation of the innermost intercostal muscles?
Intercostal nerves; T1-T11
172
(Table 3.2: Muscles of the thoracic wall)
What is the function of the innermost intercostal muscles?
Acts with internal intercostal muscles
173
(Table 3.2: Muscles of the thoracic wall)
What is the superior attachment of the subcostales muscles?
Internal surface (near angle) of lower ribs
174
(Table 3.2: Muscles of the thoracic wall)
What is the inferior attachment of the subcostales muscles?
Internal surface of second or third rib below
175
(Table 3.2: Muscles of the thoracic wall)
What is the innervation of the subcostales muscles?
Related intercostal nerves
176
(Table 3.2: Muscles of the thoracic wall)
What is the function of the subcostales muscles?
May depress ribs
177
(Table 3.2: Muscles of the thoracic wall)
What is the superior attachment of the transversus thoracis muscles?
Inferior margins and internal surfaces of costal cartilages of second to sixth ribs
178
(Table 3.2: Muscles of the thoracic wall)
What is the inferior attachment of the transversus thoracis muscles?
Inferior aspect of deep surface of body of sternum, xiphoid process, and costal cartilages of ribs IV-VII
179
(Table 3.2: Muscles of the thoracic wall)
What is the innervation of the transversus thoracis muscles?
Related intercostal nerves
180
(Table 3.2: Muscles of the thoracic wall)
What is the function of the transversus thoracis muscles?
Depresses costal cartilages
181
The muscles of the thoracic wall, together with muscles between the vertebrae and ribs posteriorly do what to control breathing?
Alter the position of the ribs and sternum and so change the thoracic volume during breathing.
182
Which are the muscles between the vertebrae and ribs posteriorly that affect breathing?
i.e., the LEVATORES COSTARUM and SERRATUS POSTERIOR SUPERIOR and SERRATUS POSTERIOR INFERIOR muscles.
183
What do the muscles of the thoracic wall and levatores costarum, serratus posterior superior/inferior do as well as change thoracic volume?
Reinforce the thoracic wall
184
What are the intercostal muscles?
Three flat muscles found in each intercostal space that pass between adjacent ribs (3.27).
185
How are the intercostal muscles named?
Individual muscles in this group are named according to their positions.
186
Which intercostal muscles are the most superficial?
The external intercostal muscles
187
Which intercostal muscles lie in the middle?
The internal intercostal muscles are sandwiches between the external and innermost muscles.
188
Which intercostal muscles are the deepest?
The innermost intercostal muscles
189
What are the intercostal muscles innervated by?
The related intercostal nerves
190
What do the intercostal muscles provide collectively?
Structural support for the intercostal spaces during breathing.
191
As a group, what else do the intercostal muscles do (as well as provide support)?
They can also move the ribs.
192
How many external intercostal muscles are there?
11 pairs
193
Which muscles extend from the inferior margins (lateral edges of costal grooves) of the ribs above to the superior margins of the ribs below?
EXTERNAL INTERCOSTAL MUSCLES.
194
How do the muscle fibres of the external intercostals run?
When the thoracic wall is viewed from a lateral position, they pass obliquely anteroinferiorly (Fig. 3.27).
195
Where do the external intercostal muscles extend?
The muscles extend around the thoracic wall from the regions of the tubercles of the ribs to the costal cartilages.
196
What is the external intercostal membrane?
Where each layer of intercostal muscles continues as a thin connective tissue aponeurosis (termed the EXTERNAL INTERCOSTAL MEMBRANE).
197
When are the external intercostal muscles most active?
In inspiration
198
How many internal intercostal muscles are there?
11 pairs
199
Which muscles pass between the most inferior lateral edge of the costal grooves of the ribs above, to the superior margins of the ribs below?
INTERNAL INTERCOSTAL MUSCLES
200
Where do the internal intercostal muscles extend from?
Parasternal regions, where the muscles course between adjacent costal cartilages, to the angle of the ribs posteriorly (Fig. 3.27)
201
Where do the internal intercostal muscles continue to?
This layer continues medially toward the vertebral column, in each intercostal space, as the INTERNAL INTERCOSTAL MEMBRANE.
202
Describe the muscle fibres of the internal and external intercostal muscles in relation to each other.
They pass in the opposite direction.
203
How do the muscle fibres of the internal intercostals run?
When the thoracic wall is viewed from a lateral position, the muscle fibres pass obliquely posteroinferiorly.
204
When are the internal intercostal muscles most active?
During expiration
205
Which are the least distinct of the intercostal muscles?
The INNERMOST INTERCOSTAL MUSCLES
206
How do the innermost intercostal muscles run?
The fibres have the same orientation as the internal intercostals (Fig. 3.27)
207
When are the innermost intercostal muscles most evident?
In the lateral thoracic wall.
208
Where do the innermost intercostals extend?
Between the inner surfaces of adjacent ribs from the medial edge of the costal groove to the deep surface of the rib below.
209
What is important about the plane between the innermost and internal intercostal muscles?
The neurovascular bundles associated with the intercostal spaces pass around the thoracic wall in the costal grooves in a plane between these muscles.
210
The subcostales are in the same plane as which muscles?
The innermost intercostals
211
Describe the subcostales.
They span multiple ribs and are more numerous in lower regions of the posterior thoracic wall (Fig. 3.28A).
212
Where do the subcostales extend?
From the internal surfaces of one rib to the internal surface of the second (next) or third rib below.
213
How do the subcostales fibres run?
Their fibres parallel the course of the internal intercostal muscles and extend from the angle of the ribs to more medial positions on the ribs below.
214
Where are the transversus thoracic muscles found?
The TRANSVERSUS THORACIC MUSCLES are found on the deep surface of the anterior thoracic wall (Fig. 3.28B) and in the same plane as the innermost intercostals.
215
Where do the transversus thoracic muscles originate?
From the posterior aspect of the xiphoid process, the inferior part of the body of the sternum, and the adjacent costal cartilages of the lower true ribs.
216
How do the transversus thoracic muscles pass?
Superiorly and laterally to insert into the lower borders of the costal cartilages of ribs III to VI.
217
What is the transversus thoracic muscles function?
They most likely pull ribs III to VI inferiorly.
218
Where do the transversus thoracic muscles lie?
Deep to the internal thoracic vessels, and secure these vessels to the wall.
219
What do vessels that supply the thoracic wall consist mainly of?
Posterior and anterior intercostal arteries, which pass around the wall between adjacent ribs in intercostal spaces (Fig. 3.29).
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Where do the arteries supplying the thoracic wall originate from?
The aorta and internal thoracic arteries
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Where do the aorta and internal thoracic arteries arise from?
The subclavian arteries in the root of the neck
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Describe the layout of the arterial supply around the thoracic wall.
Together, the intercostal arteries form a basket-like pattern of vascular supply around the thoracic wall.
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Where do posterior intercostal arteries originate from?
Vessels associated with the posterior thoracic wall
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Where are the upper two posterior intercostal arteries on each side derived from?
The SUPREME INTERCOSTAL ARTERY
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Where does the supreme intercostal artery travel?
It descends into the thorax as a branch of the costocervical trunk in the neck.
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What is the costocervical trunk a branch of?
A posterior branch of the subclavian artery (Fig. 3.29).
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Where do the remaining 9 pairs (i.e. not the upper 2) of posterior intercostal arteries arise from?
The posterior surface of the thoracic aorta.
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Why are the right intercostal arteries longer than the left?
Because the aorta is on the left side of the vertebral column (where they arise), those posterior intercostal vessels passing to the right side of the thoracic wall cross the midline anterior to the bodies of the vertebrae and therefore are longer than the corresponding vessels on the left.
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What branches do the posterior intercostal arteries supply?
In addition to having numerous branches that supply various components of the wall, the posterior intercostal arteries have branches that accompany lateral cutaneous branches of the intercostal nerves to superficial regions.
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Where do the anterior intercostal arteries originate?
Directly or indirectly as lateral branches from the internal thoracic arteries (Fig. 3.29)
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Where does each internal thoracic artery arise?
As a major branch of the subclavian artery in the neck.
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Where do the internal thoracic arteries pass?
Anteriorly over the cervical dome of the pleura and descends vertically through the superior thoracic aperture and along the deep aspect of the anterior thoracic wall.
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Where does the internal thoracic artery lie on each side?
Posterior to the costal cartilages of the upper six ribs and about 1 cm lateral to the sternum.
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Where does the internal thoracic artery divide into two terminal branches?
At approximately the level of the sixth intercostal space
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What are the two terminal branches of the internal thoracic artery?
SUPERIOR EPIGASTRIC ARTERY
MUSCULOPHRENIC ARTERY
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Where does the superior epigastric artery run?
It continues inferiorly into the anterior abdominal wall (Fig. 3.29)
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Where does the musculophrenic artery run?
It passes along the costal margin, goes through the diaphragm, and ends near the last intercostal space.
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Anterior intercostal arteries that supply the upper six intercostal spaces arise as ____?
Lateral branches from the internal thoracic artery
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Anterior intercostal arteries supplying the lower spaces arise from the ___?
Musculophrenic artery
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In each intercostal space, the anterior intercostal arteries usually has two branches.
Where?
One passes below the margin of the upper rib.
The other passes above the margin of the lower rib
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The anterior intercostal artery usually has two branches in each intercostal space. What does the inferior branch do?
Meets a collateral branch of the posterior intercostal artery.
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What is the significance of the anterior and posterior intercostal vessels overlapping?
Their distributions overlap and can develop anastomotic connections.
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The ________ intercostal arteries are generally smaller than the _________ vessels.
Anterior are smaller than posterior.
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What branches do internal thoracic arteries give rise to?
In addition to anterior intercostal arteries and a number of other branches, the internal thoracic arteries give rise to perforating branches that pass directly forward between the costal cartilages to supply structures external to the thoracic wall.
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Where do the perforating branches of the internal thoracic arteries travel?
With the anterior cutaneous branches of the intercostal nerves.
246
Describe the venous drainage from the thoracic wall.
It generally parallels the pattern of arterial supply (Fig. 3.30)
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Where do the intercostal veins drain?
Centrally, the intercostal veins ultimately drain into the azygos system of veins or into INTERNAL THORACIC VEINS
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What do internal thoracic veins connect with?
The BRACHIOCEPHALIC VEINS in the neck.
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What does the upper posterior intercostal veins on the left side often come together and form?
The LEFT SUPERIOR INTERCOSTAL VEIN
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What does the left superior intercostal vein drain into?
The left brachiocephalic vein
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What does the upper posterior intercostal veins on the right side often come together and form?
The RIGHT SUPERIOR INTERCOSTAL VEIN
252
Where does the right superior intercostal vein drain into?
The AZYGOS VEIN
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Where do lymphatic vessels of the thoracic wall drain into?
Mainly into lymph nodes associated with the
- internal thoracic arteries (PARASTERNAL NODES)
- heads and necks of ribs (INTERCOSTAL NODES)
- diaphragm (DIAPHRAGMATIC NODES).
Fig. 3.31
254
What are the lymph nodes associated with the internal thoracic arteries called?
PARASTERNAL NODES
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What are the lymph nodes associated with the heads and necks of ribs called?
INTERCOSTAL NODES
256
What are the lymph nodes associated with the diaphragm called?
DIAPHRAGMATIC NODES
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Where are diaphragmatic nodes ofund?
- Posterior to the xiphoid
- At sites where the phrenic nerves penetrate the diaphragm.
- Also in regions where the diaphragm is attached to the vertebral column
258
Where do parasternal nodes drain into?
BRONCHOMEDIASTINAL TRUNKS
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As well as parasternal nodes, what else drains into bronchomediastinal trunks?
Intercostal nodes in the upper thorax
260
Where do intercostal nodes in the lower thorax drain into?
THORACIC DUCT
| Upper = bronchomediastinal trunks
261
What do nodes associated with the diaphragm interconnect with?
- Parasternal, prevertebral and juxta-esophageal nodes
- BRACHIOCEPHALIC NODES
- LATERAL AORTIC/LUMBAR NODES
262
Where are brachiocephalic nodes found?
Anterior to the brachiocephalic veins in the superior mediastinum
263
Where are lateral aortic/lumbar nodes found?
In the abdomen
264
Where do superficial regions of the thoracic wall drain mainly into?
AXILLARY LYMPH NODES or parasternal nodes.
265
Where are axillary lymph nodes ofund?
In the axilla
266
What is the innervation of the thoracic wall?
Mainly by the INTERCOSTAL NERVES
267
What are the intercostal nerves?
Anterior rami of spinal nerves T1 to T11
268
Where do the intercostal nerves lie?
In the intercostal spaces between adjacent ribs.
269
What is the subcostal nerve?
Anterior ramus of spinal nerve T12
270
Where is the subcostal nerve found?
Inferior to rib XII (Fig. 3.32)
271
Where does a typical intercostal nerve pass?
Laterally around the thoracic wall in an intercostal space
272
Which is the largest branch of the intercostal nerve?
The LATERAL CUTANEOUS BRANCH
273
Where does the lateral cutaneous branch of the intercostal nerve pierce?
The lateral thoracic wall
274
What does the lateral cutaneous branch of the intercostal nerve divide into, and what does that innervate?
An anterior and a posterior branch that innervate the overlying skin.
275
What do the intercostal nerves end as?
ANTERIOR CUTANEOUS BRANCHES
276
Where do the anterior cutaneous branches emerge?
Either parasternally, between adjacent costal cartilages, or laterally to the midline, on the anterior abdominal wall.
277
What do the anterior cutaneous branches supply?
The skin
278
In addition to these major branches of the intercostal nerve, what else can be found?
Small collateral branches in the intercostal space running along the superior border of the lower rib.
279
In the thorax, the intercostal nerves carry somatic motor innervation to ___?
The muscles of the thoracic wall (intercostal, subcostal, and transversus thoracis muscles)
280
In the thorax, the intercostal nerves carry somatic sensory innervation from ___?
The skin and parietal pleura
281
In the thorax, the intercostal nerves carry ______________ ___________ ______ to the ________
postganglionic sympathetic fibres; periphery
282
What is sensory innervation of the skin overlying the upper thoracic wall supplied by?
Cutaneous branches (supraclavicular nerves), which descend from the cervical plexus in the neck.
283
In addition to innervating the thoracic wall, intercostal nerves innervate other regions.
The anterior ramus of T1 contributes to ____
the brachial plexus
284
In addition to innervating the thoracic wall, intercostal nerves innervate other regions.
The lateral cutaneous branch of the _____ _____ ____
second intercostal nerve (the INTERCOSTOBRACHIAL NERVE)
285
The intercostobrachial nerve contributes to ___?
Cutaneous innervation of the medial surface of the upper arm
286
What do the lower intercostal nerves supply?
The muscles, skin and peritoneum of the abdominal wall.
