Organ
Left lung
Two-lobed lung sharing the chest with the heart
High-yield
There is no usual left middle lobe: the lingula is part of the superior lobe. Segment counts vary with combined bronchial territories.
Overview
The left lung has superior and inferior lobes separated by an oblique fissure. The anterior cardiac notch accommodates the heart, with the lingula projecting below it from the superior lobe.
Reference facts
- Location
- Left hemithorax between the thoracic inlet and diaphragm
- Parts
- Superior and inferior lobes, including the lingula in the superior lobe; usually eight to ten counted segments
- Blood supply
- Left pulmonary arterial branches and systemic bronchial arteries
- Innervation
- Left pulmonary plexus with autonomic and visceral sensory fibers
- Relations
- Heart medially and anteriorly; aortic arch and descending aorta on the mediastinal side
- Venous/Lymphatic drainage
- Pulmonary veins to the left atrium; lymph through pulmonary, hilar and mediastinal nodes, with some cross-midline routes
- Function
- Pulmonary gas exchange within the available left thoracic space
Clinical correlation
Knowing the positions of the heart and fissure helps localize left-sided opacities. Incomplete or accessory fissures can make the usual lobar outlines less obvious.
Frequently asked questions
Where is the left lung located?
The left lung lies left hemithorax between the thoracic inlet and diaphragm.
What does the left lung do?
Pulmonary gas exchange within the available left thoracic space.
What are the parts of the left lung?
Superior and inferior lobes, including the lingula in the superior lobe; usually eight to ten counted segments.
What is the blood supply of the left lung?
The left lung is supplied by the left pulmonary arterial branches and systemic bronchial arteries.