Pleura and Lungs: Flashcards
Pulmonary cavity
Lined by serous membrane → pleural membrane
- Double layer – it is continuous at the level of the hilum
- Outer parietal pleura - lines pulmonary cavities
- Inner layer - visceral pleura, covers lung surface and extend
into fissures
- Layers continuous with each other around hilum of lung
Pleural cavity:
space between visceral and parietal pleura – contains serous fluid which prevents friction between lung and thoracic wall while breathing – also a potential space
Parietal pleura
Consists of different parts:
- Costal – lines inside of the ribcage
- Mediastinal – lines the media sternum (outside of pericardium)
- Diaphragmatic – on top of the diaphragm
- Cervical – part within the neck region
Endothoracic fascia (thin layer) Is deep to the pleural layer (thick and transparent) and suprapleural membrane is the top part of the endothoracic fascia
Pleural reflection lines
Relatively abrupt change in the direction of parietal pleura, it reflects from one wall of pleural cavity to another
- Sternal line – left and right
- Costal line – costal pleura becomes diaphragmatic pleura
- Vertebral line
Pleural cavity borders
Pleural cavity extends below inferior border of lungs.
Inf. Margin of pleura:
T12- at midline position
Midaxillary line
– Rib 10
Midclavicular line
– Rib 8
Xiphisternal joint at anterior midline
- Inferior border of lung is two ribs above pleural margin
- Anteriorly, lungs and pleural margin meet near xiphisternal joint
Pleural recesses
Pleural recesses
Lungs do not occupy pulmonary cavities completely during expiration
– potential pleural spaces
Costodiaphragmatic recess - Peripheral diaphragmatic pleura contact with lowermost costal pleura Costomediastinal recess - Posterior to sternum - Costal pleura meets mediastinal pleura
Blood supply
Parietal pleura:
- Intercostal (ant. And post.) arteries and veins
Blood supply
Visceral pleura: Same as lungs
- Bronchial arteries. (1 right and two left)
- Right bronchial vein → drains into v. azygos
- Left bronchial vein → drains accessory hemi - azygos or left sup.
intercostal vein - Pulmonary veins, two on each side
Each lung has:
Apex (above rib 1)
• Base
• Surfaces
Costal
Mediastinal
Diaphragmatic
• Borders
Ant., inf. and post.
• Lobes and fissures
R lung is shorter, wider, larger & heavier than L – Why?
Because heart is more towards left hand side, so less space for left lung to develop
Right lung:
Sup. lobe Middle lobe Inf. lobe Horizontal fissure Oblique fissure
Left lung
Sup. lobe
Inf. lobe
Oblique fissure
Lingula
Fissures In the right lung
the short horizontal fissure runs horizontally from the oblique fissure up to the anterior border and separates a wedge-shaped middle lobe from the upper lobe. The fissures facilitate a uniform expansion of whole lung for more air intake during respiration.
Hilum of lung
Hilum of lung
– wedge-shaped area of medial surface of lung, point at which structures forming the root enters and leaves the lung
Relations R hilum
Ant: VCS and n. phrenicus
• Post: V. azygos, n. vagus and esophagus
• Sup: Arch v. azygos
• Inf: Pulmonary lig.
Relations L hilum:
Ant: N. phrenicus
• Post: N. vagus and aorta
• Sup: Arch aorta
• Inf: Pulmonary lig.
Root of lung
- Anchor lungs to thorax - Attachment of lung to mediastinum
- Parietal and visceral layers of pleura are continuous
- Pulmonary ligament - fold of parietal pleura extending beyond
root downwards
Contents (at hilum)
- Pulmonary a.: superiormost. On left
On right “eparterial” bronchus is sup.
- Main bronchus: middle posterior boundary
- Sup. Pulmonary vv.: anteriormost
- Inf. Pulmonary vv: inferiormost
Root of lung vs Hilum
The root of the lung is the collection of structures that connect the lung to the mediastinum. This includes the pulmonary arteries and veins, the primary bronchi and bronchial arteries, and the pulmonary nerve plexuses and lymphatics.
The hilum is the place on the lung where these structures enter and leave the lung.
Tracheobronchial tree
Tracheobronchial tree
1. Trachea o Begins below larynx o C-shaped cartilage rings o Ends at sternal angle - carina marks line of separation o (divide into L and R bronchi) o Passes anterior to oesophagus
- Divides into
• Main (primary) bronchi – R & L bronchus.
R: wider, shorter, more vertically placed. – more likely to catch shit in
it
L passes inferolat., inf. to arch aorta, ant. esophagus & thoracic aorta - Divides into
• Lobar (secondary) bronchi – one going to each lobe
4. Divides into
• Segmental (tertiary) bronchi which supply bronchopulmonary
segments
Bronchopulmonary segments
• Usually 10 R & 8-10 for L lung
• Largest subdivision of a lobe
- Segmental bronchi divide into conducting bronchioles
- Conducting bronchioles end as terminal bronchiole
- Respiratory bronchioles
- Alveolar ducts leading to alveolar sacs (collection of alveoli)
Tracheobronchial tree characteristics:
- Pyramid shaped
- Each one surrounded by own connective tissue septa separate
from adjacent segments - Independent supply by segmental bronchus and tertiary
branch of pulmonary artery - Named according to segmental bronchus
- Drained by intersegmental parts of pulmonary veins located in CT between segments
- Each segment can be surgically removed – without affecting
function of the lung - Has own blood and air supply and connective tissue septa –
can remove a bronchopulmonary segment – limits spread of
disease within lung
performed to investigate the trachea and the bronchi, and also to retrieve any inhaled particles
Bronchoscopy
Arterial supply of lungs
- Bronchi and their branches and all connective tissue
- Visceral pleura
> Right bronchial artery (Arises from post. intercostal or sup.
left bronchial)
> Two left bronchial arteries (Arises from thoracic aorta)
Provides nutrients to lung tissue - Parietal pleura
> Intercostal arteries - Alveoli
> Pulmonary artery brings deoxygenated blood from heart
Venous drainage of lungs
-Pulmonary veins , two on each side:Oxygenated blood from lungs
Bronchial veins: (2)
right bronchial vein → v. azygos
left bronchial vein → acc. hemi-azygos or left sup. intercostal
vein
Lymphatic drainage of lungs
Goes into 2 places
- Superficial plexus - deep to visceral pleura.
- Deep plexus (submucosa)
- Superficial plexus - deep to visceral pleura.
- Drains lung tissue & visc. pleura
- Drains into broncho- pulmonary nodes at hilum.
- Rest of drainage the same as for the deep plexus
- Deep plexus (submucosa)
- Drains structures that form root of lung
- All lobes R lung drain to:
pulmonary→ broncho-pulmonary→ inf. tracheo-bronchial→ sup. tracheobronchial→broncho- mediastinal trunk→thoracic duct or R lymphatic duct - L sup. lobe follows above mentioned pathway on left side
- L inf. lobe crosses from left inf. to right sup. tracheo-bronchial
nodes, and then follows same route as lymph from right lung
Innervation of lungs
• Ant. and post. pulmonary plexuses, ant. and post. to root of
lung
• Branches of this plexus originate from the sympathetic trunks
(T2- T5) and parasympathetic from vagus nn.
• Plexus contains parasympathetic, sympathetic and visc. aff.
fibers
• Distributed along branches of the airways and vessels
o Vagus constricts bronchioles
o Sympathetic system dilates bronchioles
o Visc. aff. fibers of plexus for reflexes and pain
Right vagus
• Enters mediastinum ant. to right subclavian artery
• R recurrent laryngeal n.
• Runs postero inf. on R side trachea, post. to R brachiocephalic
v., SVC and. root R lung
• Divides into branches for for R pulmonary plexus
• Leaves plexus as single nerve → esophageal plexus
Left vagus
• Enters between left comm. carotid artery & L subclavian artery • L recurrent laryngeal n. • Passes post to root left lung • Divides into branches for - L pulmonary plexus -Leaves plexus as single nerve → esophageal plexus
N. Phrenicus
• Between subclavian artery and origin brachiocephalic vein
• Ant. to root lung
• Right - Passes along right side R brachiocephalic vein, SVC.,
RA, IVC
• Left - Crosses left surface of arch aorta, superficial to LA and LV
• Motor and sensory to diaphragm
• Sensory pericardium and mediastinal pleura
Anterior view of chest markings
Pleural markings
Lung markings
Cardiac notch
Oblique fissure- spinous proc. of T2 posteriorly to 6th costal cartilage anteriorly
Horizontal fissure - runs at level of 4th costal cartilage and rib, meets oblique fissure in midaxillary line
Trachea
Recesses
posterior view of chest markings
Vertebra prominens = C7 Spine T1 Oblique fissure Lung markings Pleural markings
Relationship between Lungs and Pleura
Parietal pleura extends approximately two ribs inferior to the lung
( 2 ribs between bottom of lung and pleura)
