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Thoracic Wall & Lungs
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Thoracic Cavity Organization
3 major spaces
mediastinum
right / left pulmonary cavities
2 apertures
superior / inferior
True Ribs
Vertebrocostal
(Ribs 1 - 7)
Attach directly to the sternum via costal cartilages
False Ribs
Vertebrochondral
(Ribs 8 - 10)
Attach to the costal margin
Floating Ribs
(Ribs 11 & 12)
Do not attach to the sternum
Typical Ribs
(Ribs 3 - 9)
- Head (2 facets)
- Neck
- Tubercle
- Body / Angle
- Costal groove
- Costal cartilage
Superior Atypical Ribs
(Ribs
1-2
, 10-12)
1
st
Rib:
- grooves for subclavian BVs
- 1 articular facet on head
- tubercles for ant. / mid. scalene
2
nd
Rib:
- 1 articular facet
- tubercle for posterior scalene
Inferior Atypical Ribs
(Ribs 1-2,
10-12
)
Rib 10:
- 1 articular facet
Ribs 11 & 12:
- 1 articular facet
- floaters
- no necks / tubercles
Which is the only atypical rib to have similar structure at the head as the typical ribs?
Rib 2
(2 articular facets)
Anatomical appearance of the breast
- mainly subcutaneous fat
- modified apocrine sweat gland
- lobules drains into lactiferous ducts
- supported by suspensory ligaments
- 2/3 pec. major & 1/3 serratus ant.
- retromam. space = movement
- lateral region = axillary tail
Anatomical levels of breast / nipples
Breast: ribs 2-6
Nipple: 4
th
intercostal space (males!)
Arterial supply to the breast
1. Lateral thoracic a. (lateral mammary branches)
2. Internal thoracic a. (medail mammary branches)
3. Post. intercostals (2-4 intercostal spaces)
Venous drainage to the breast
1. Axillary v. (via lat. mammary vv.)
2. Internal thoracic v. (via medial mammary vv.)
Venous drainage can reach the azygous system via intercostal veins
Innervation of the breast
Ant. / Lat. cutaneous branches of 2
nd
- 6
th
intercostal nn.
(sensory / smooth muscle signals)
Innervation of the nipple
4
th
intercostal n.
Lymphatic drainage of the breast
Subareolar lymphatic plexus
75% -> axillary nodes -> r. lymphatic / thoracic ducts
(some in parasternal nodes)
Lat. branches of post. intercostals -> azygous system -> thoracic duct
some drainage into subdiaphragmatic nodes / liver
Anterior muscles of forceful respiration
Pec. major
clavipectoral fascia
Pec. minor
Major contributors of respiration
External intercostals
- membranous anteriorly
Internal intercostals
- membranous posteriorly
Innermost intercostals
- membranous anteriorly & posteriorly
Which intercostal muscles are continuous w/ abdominal muscles?
External intercostals (external oblique)
Internal intercostals (internal oblique)
Arterial supply to thorax
2 main sources:
posterior intercostal aa.
- most arises from thoracic a.
- upper 2 arise from superior thoracic a. (branch of costocervical trunk)
anterior intercostal aa.
(usually paired)
- arises form internal thoracic aa. (subclavian aa.)
What are the terminal branches of the internal thoracic aa. in the thorax?
1) superior epigastric aa.
2) musculophrenic aa.
- supplies the lower spaces
- anastamoses w/ post. intercostals)
Venous drainage of thorax
Parallels arterial supply except for azygos system
Ultimately drains via 2 routes:
1) Internal thoracic vv.
- drains into brachiocephalic vv.
2) Azygos system
- drains into superior vena cava
Innervation of thorax
- intercostal n. (ant. rami T1-11)
- subcostal n. (ant. rami T12)
- intercostal branches carry
sympathetic motor to smooth muscle
(i.e. vasculature / erector pili / hair follicles)
Intercostal Spaces: Boundaries & Contents
lateral border = internal intercostal m.
medial border = innermost intercostal m.
Contents (superior to inferior)
VAN + collateral branches
Structures that pass thru diaphragm @ T8
Caval hiatus passes through central tendon:
- IVC
- R. Phrenic n.
- Pericardiacophrenic a.
Structures that pass thru diaphragm @ T10
Esophageal hiatus passes through muscular diaphragm:
- Esophagus
- Vagus n.
Structures that pass thru diaphragm @ T12
Aortic hiatus passes posterior to diaphragm:
- Thoracic aorta
- Thoracic duct
Innervation / Blood Supply to Diaphragm
Blood supply
- branches of abdominal aorta (major)
- thoracic aorta / intercostals / pericardiacophrenic / musculophrenic (minor)
Innervation
- Phrenic n. (C3-C5) penetrate diaphragm and innervate it from underneath
At what point do the parietal and visceral pleura become continuous?
Hilum of the lung
(T5-T7) pleura reflects back on itself
extends inferiorly as pulmonary ligament
Endothoracic fascia
- loose CT layer
- separates the parietal pleura from internal surface of thoracic wall
Costodiaphragmatic Recess
Below 6
th
rib (MCL)
Below 8
th
rib (MAL)
Lobes of the lungs
Each lung has 10 bronchopulmonary segments
Right Lung (3 lobes)
- separated by horizontal / oblique fissures
Left Lung (2 lobes)
- separated by oblique fissure
Right Lung - Mediastinal surface
Anteriorly:
- groove for SVC
- cardiac impression
- pulmonary a.
- pulmonary v.
Posteriorly:
- groove for azygos arch
- groove for esophagus
- Bronchus
Left Lung - Mediastinal surface
Anteriorly:
- large cardiac impression
- groove for subclavian a.
- pulmonary v.
- lingula
Posteriorly:
- groove for aortic arch / descending aorta
- pulmonary a.
- bronchus
- pulmonary v.
Right bronchial tree
Trachea -> R. main bronchus
-> R. superior (eparterial) bronchus
-> R. middle / inferior bronchi
Arterial supply to lung
Bronchial arteries
(branches of descending aorta)
Venous drainage of lung
Bronchial veins
(right into azygos v. / left into hemiazygos system)
Why can't blood oxygenation reach 100%?
Inside lungs,
bronchial veins unite w/ pulmonary v.
Delivers low oxygenated blood to right atrium
Thoracic autonomics
Parasympathetics
- Vagus n. (constrict)
Sympathetics
- sympathetic trunks (dialate)
Author
mnm2186
ID
31858
Card Set
Thoracic Wall & Lungs
Description
Exam 3
Updated
2010-09-14T05:18:43Z
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