Chapter 5 - Lungs Flashcards
Anterior border of lung
- Thin and short
- On right, corresponds to costomediastinal line
- On left, shows cardiac notch below level of 4th costal cartilage
Posterior border of lung
- Thick
- Corresponds to medial margins of heads of ribs
- Extends from C7-T10
Inferior border of lung
-Separates base from costal and mediastinal surfaces
Medial surface of lung
- Vertebral and mediastinal part
- Vertebral relations: Vertebral body, intervertebral discs, splanchnic N, posterior intercostal vessels
- Mediastinal relations: Mediastinal septum, cardiac impression, hilum
Fissures of right lung
- Horizontal
- From anterior border
- Runs at level of 4th costal cartilage
- Joins oblique fissure in midaxillary line - Oblique
- Runs downwards and forwards
- Makes lower lobe more posterior and upper and middle lobes more anterior.
Define root of lung
- A short, broad pedicle that connects medial surface of lung to mediastinum.
- Formed by structures going in and coming out of the lung.
- Lie opposite T5, T6, T7.
Contents of root of lung
- L-Principal bronchus; R-Eparterial, hyperarterial bronchus
- 1 Pulmonary A
- 2 Pulmonary V- superior, inferior
- Bronchial A- R-1, L-2
- Bronchial V
- Anterior, posterior pulmonary plexus
- Lymphatics
- Bronchopulmonary lymph nodes
- Areolar tissue
Arrangement of structures in root of lung
Posterior to anterior
- Eparterial/hyperarterial/principal bronchus, bronchial vessels, posterior pulmonary plexus
- Pulmonary A
- Superior, inferior pulmonary V
- Anterior pulmonary plexus, lymph nodes and vessels
Relations of root of lung
ANTERIORLY
Common: Phrenic N, Musculophrenic A, Anterior pulmonary plexus
Right: Superior vena cava, Right atrium
POSTERIORLY
Common: Vagus N, Posterior pulmonary plexus
Left: Descending thoracic aorta
SUPERIORLY
Right: Azygos V
Left: Arch of aorta
INFERIORLY
Pulmonary ligament
Blood supply of lungs
- Right bronchial artery from 3rd right posterior intercostal artery
- Left bronchial arteries from descending thoracic aorta
- Right bronchial vein empties into azygos vein
- Left bronchial vein empties into hemiazygos vein
Lymphatic drainage of lungs
- Bronchopulmonary lymph nodes
- Superficial vessels drain peripheral lung tissue and have many valves
- Deep vessels drain bronchial tree, connective tissue septa and have no valves
Paraympathetic nerve supply of lungs
From vagus
- Motor fibres to bronchial muscles: cause bronchospasm
- Secretomotor fibres to mucous glands
- Sensory fibres: for stretch and cough reflex
Sympathetic nerve supply of lungs
- 2-5th sympathetic ganglia
- inhibitory
Features of bronchopulmonary segments
- Well defined anatomical, functional, surgical segments
- Each aerated by tertiary/segmental bronchus
- Pyramidal with apex towards root and base towards periphery
- Each has segmental bronchus, segmental A, autonomic N, lymph vessels
- Segmental venules lie in connective tissue betwwen segments
- During infection of segment, it is usually restricted to segment.
Bronchial asthma
- bronchospasm of smooth muscles in wall of bronchioles
- difficulty during expiration
- accompanied by wheezing
- Rx: Epinephrina, sympathomimetic drug
