Thoracic Wall Flashcards
1
Q
Thoracic Wall
A
- Rigid but flexible
- Constantly in motion
2
Q
Boundaries Forming the Thoracic Wall
A
- Skin
- Subcutaneous tissue
- Thoracic cage
- Ribs and costal cartilage
- Sternum
- Thoracic vertebrae and IVD
- Muscle (intercostals, pecs)
- Fascia
3
Q
Thoracic Wall Function
A
- Protect thoracic and abdominal organs
- Respiration
- Muscle attachment
4
Q
Thoracic Cavity
A
- Space enclosed by the thoracic cage, intercostal muscles and diaphragm
- Superior thoracic aperture
- Inferior thoracic aperture
5
Q
Superior Thoracic Aperture
A
- Slopes antero-inferiorly
- Communication with neck and upper limb
6
Q
Boundaries of Superior Thoracic Aperture
A
- Posterior: T1 body
- Lateral: rib 1 and cartilage
- Anterior: superior manubrium
7
Q
Inferior Thoracic Aperture
A
- Posterior is more inferior than anterior
- Larger and enclosed by diaphragm
- Passageway to/from abdominal cavity pass
- Posterior or through diaphgram
8
Q
Boundaries of Inferior Thoracic Aperture
A
- Body of T12 vertebra
- Rib 12 and distal end of rib 11
- Costal cartilage of ribs 7 – 10
- Xiphoid process
9
Q
Infrasternal Angle (Subcostal Angle)
A
- Formed by costal margin and xiphisternal joint
10
Q
Ribs
A
- Flat bones
- Active hematopoietic tissue (Red bone marrow)
11
Q
True Ribs
A
- Vertebrosternal ribs (1-7)
12
Q
False Ribs
A
- Vertebrochondral ribs (8-10)
13
Q
False, Floating Ribs
A
- Free ribs (11, 12)
14
Q
Typical Ribs
A
- Ribs 3-9
15
Q
Atypical Ribs
A
- Ribs 1, 2, 10-12
16
Q
Typical Ribs
A
- Head
- Neck
- Tubercle
- Body
17
Q
Head of Typical Ribs
A
- 2 facets for articulating with 2 adjacent vertebrae and disc between
18
Q
Tubercle of Typical Ribs
A
- Articular part that articulates with the TP of the corresponding vertebra, non-articular part
19
Q
Body of Typical Ribs
A
- Costal angle and costal groove
20
Q
1st Rib
A
- Morphology
- Single facet on the head (articulates with one vertebral body)
- Grooves for subclavian vessels
- Scalene tubercle
21
Q
2nd Rib
A
- Noticeable tuberosity for serratus anterior
22
Q
Ribs 10-12
A
- Single facet on the head (articulates with one vertebral body)
23
Q
Ribs 11-12
A
- Single facet on the head (articulates with one vertebral body)
- Short and lack a neck and tubercle (no TP articulation
24
Q
Costal Cartilages
A
- Provide flexibility
- Attach ribs to sternum
25
Costal Cartilage Attachments
- Directly: ribs 1-7
- Indirectly: ribs 8-10
- Forms costal margin
26
Intercostal Spaces
- Numbered based on the superior rib
- Filled by intercostal muscles and membranes
- 11 of them
27
Intercostal Spaces
- Each contains 2 sets of intercostal vessels and nerves
| - Space changes dimensions with respiration
28
Subcostal Space
- Below rib 12
29
Thoracic Vertebrae (12)
- Bilateral costal facets on postero-lateral vertebral bodies
- Superior and inferior costal facets for rib head articulation
- Demifacets or full facets
30
Costal Facets on TP
- Articulation with rib tubercle
| - T11 and 12 do not have costal face
31
Sternum
- Protects underlying viscera
| - Rib attachment
32
Parts of the Sternum
- Manubrium
- Body
- Xiphoid process
33
Manubrium of Sternum
- Spans vertebral level T3-4)
- Jugular notch (vertebral level T2)
- Clavicular notches
- Synchondroses of 1st rib
34
Body of Sternum
- Spans vertebral level T5-9)
- Costal notches for ribs 3-7
- Transverse ridges (lines of fusion)
- Represents the fuses of 4 separate sternebrae
35
Xiphoid Process of Sternum
- Vertebral level T10
| - Appearance varies
36
Manubrialsterno Joint (Sternal Angle)
- Part of the sternum
| - Located T4/5
37
Xiphisternal Joint
- Located T9 in supine position
- Level of central tendon of diaphragm
- Inferior limit of heart, superior limit of liver
38
Costovertebral Joint
- Rib head and vertebral body
| - Synovial joint
39
Costotransverse Joint
- Rib tubercle and TP
| - Synovial joint
40
Costochondral
- Rib with costal cartilage
| - Primary cartilaginous
41
Interchondral
- Between cartilages ribs 6-9
| - Synovial joint
42
Sternocostal Joint
- Between costal cartilages and sternum
- Strengthened by radiate ** ligaments
- 1st is primary cartilaginous, synchondrosis
- 2-7 are synovial
43
Manubriosternal Joint
- Secondary cartilaginous (fibrocartilage)
44
Xiphisternal Joint
- Primary cartilaginous
45
Sternoclavicular Joint
- Upper extremity
46
Costovertebral and Costotransverse Joints
- Also considered joints of the vertebral column
47
Joints of the Thoracic Wall
- Costovertebral
- Costotransverse
- Costochondral
- Interchondral
- Sternocostal
- Manubriosternal
- Xiphisternal
- Sternoclavicular
48
Costovertebral Joints
- Articulates with costal facets on vertebral bodies
| - Synovial joints, gliding
49
Head of Ribs 2-9
- Articulate with superior aspect of corresponding vertebra
the inferior aspect of the one above
- Intervening IVD
- 2 joint cavities separated by intra-articular ligament
supported by radiate ligaments
50
Head of Ribs 1, 10-12
- Articulate with only its corresponding vertebral body
51
Costotransverse Joint
- Synovial joint, gliding joints
- Between rib tubercle and TPs of corresponding vertebra
- Supported by ** ligaments
- Shape of articulating surfaces of TPs differs between superior and inferior ribs
- Ribs 11 and 12 do not articulate with TP therefore they do not have a tubercle
52
Rib Fracture
- Usually as a result of blunt trauma to thorax
- 4-9 most commonly injured
- Can result in injury to underlying organs
- Pulmonary laceration, hemothorax, pneumothorax
53
Flail Chest
- Life-threatening condition
| - Fracture of 3 or more adjacent ribs at 2 locations
54
Flail Chest
- Creates a free segment
- Paradoxical movement of the free segment with respiration
- Indicative of more serious underlying injuries (pulmonary contusion, cardiac tamponade)
- Leading to respiratory compromise causing hypoxia
55
Intercostal Muscles
- Span the intercostal space, attached to the ribs
| - Superior border of rib below, inferior border of rib above
56
External Intercostal Muscles
- Most superficial
- Located from rib tubercle to costochondral junction
- ** membrane spans the gap to the sternum
- Anteromedial muscle fiber direction
- Elevate rib during inspiration
57
Internal Intercostal Muscles
- Deep to external intercostals
- Muscle fibers run postero-inferior (90⁰ angle to the externals)
- Located from rib angle to sternum
- ** membrane spans the gap to about rib neck
- Depress the ribs during forced expiration
- Interchondral part (anteriorly) elevates the ribs
58
Innermost Intercostals
- Deep to internal intercostals, attached to inner part of rib
- Only found in the lateral part of the intercostal space
- Function similar to internal intercostals
59
Transversus Thoracis Muscles
- Originates from the inner surface of sternum
- Inserts onto the costal cartilages (ribs) of 2-6
- Function: depress ribs
60
Subcostal Muscles
- Internal aspect of posterior thoracic wall
- Span multiple ribs
- Function: similar to internal intercostals
61
Inspiration
- Increase volume --> decrease pressure, air flows in
62
Expiration
- Decrease volume --> increase pressure, air flow out
63
Inspiration
- Muscle contraction increases volume of thoracic cavity
- Diaphragm contraction increases vertical dimensions
- Pump handle movement increases AP diameter
- Bucket handle movement increases transverse diameter
64
Additional Muscles Recruited when Needed for More Inspiration
- External intercostals
- SCM
- Scalenes
- Anterior axio-appendicular muscles
65
Expiration
- Muscle relaxation and natural elasticity of tissue decreases volume of thoracic cavity
66
Forced Expiration
- Recruitment of additional muscles
- Abdominals
- Internal intercostals
67
Layers of the Thoracic Wall
- Skin
- Superficial fascia
- Deep fascia
- Serratus anterior or some other muscle (depends on the - - Region of the thoracic wall)
- External intercostal
- Internal intercostal
- Innermost intercostal
- Endothoracic fascia
- Parietal pleura
68
Thoracic Spinal Nerve Branches
- Posterior ramus
| - Anterior ramus (intercostal nerve)
69
Posterior Ramus
- Innervates skin over back
70
Anterior Ramus (Intercostal Nerve)
- Branches have segmental distribution
- Anterior and lateral cutaneous branches
- Branches to intercostal muscles
- Connection with rami communicantes
71
Lateral Cutaneous Branch of the 2nd and/or 3rd Thoracic Spinal Nerve
- Give rise to the intercostobrachial nerve
72
Intercostobrachial Nerve
- Supplies axilla, communicates with branches of brachial plexus
- 7th – 11th intercostal nerves also supply the abdominal wall
73
C4/5 Dermatome
- Dermatome to clavicles
74
T4 Dermatome
- Dermatome to nipples
75
T10 Dermatome
- Dermatome to umbilicus
76
Posterior Intercostal Arteries
- 1 and 2 (1st and 2nd intercostal space)
- Arises from superior intercostal artery (costocervical trunk)
- 3 – 11 arise from thoracic aorta
77
Subcostal Artery
- A branch off thoracic aorta
78
Anterior Intercostal Arteries
- 1 - 6 arise from internal thoracic artery
- 7 - 9 arise from musculophrenic artery
- Space 10 and 11 lack these arteries
79
Superior and Lateral Thoracic Arteries
- Branch off axillary artery
80
Internal Thoracic Arteries (Internal Mammary)
- Branches of the subclavian arteries
| - Descends lateral to sternum on interior aspect of thoracic wall
81
Branches of Internal Thoracic Arteries
- Pericardiophrenic
- Anterior intercostal arteries (1st 6 spaces)
- Superior epigastric and musculophrenic (terminal branches)
82
Musculophrenic Artery
- Gives off anterior intercostal arteries to spaces 7-9
83
Intercostal Neurovascular Bundle
- Found between the internal and innermost intercostal muscles
- In the costal groove
- Intercostal Nerves
- Posterior/Anterior intercostal arteries and veins
84
Intercostal Neurovascular Bundle
- Collateral branches run on the super aspect of the inferior rib
- VAN: Vein (closest to the rib), Artery, Nerve
- Below rib 12 are the subcostal nerve and vessels
85
Below the 12th Rib
- Subcostal nerve and vessels
86
Venous Drainage of Thoracic Wall
- 11 posterior intercostal veins and the subcostal vein drain into the azygos venous system
- Anterior intercostal veins drain into internal thoracic and musculophrenic veins
87
11 Posterior Intercostal Veins and Subcostal Vein
- Drain into the azygos venous system
88
Anterior Intercostal Veins
- Drain into internal thoracic and musculophrenic veins