STRUCTURE AND POSITION

• It is separated from the rest of the lung by a Horizontal Fissure.
• It separates it from Middle and Inferior lobes.
• It has an apex, part of mediastinal and costal surfaces, and most of Anterior border of the lung.

Superior Lobe of the left Lung :

• This Lobe is separated from inferior Lobe by Oblique Fissure.
• It contains apex, most of costal and mediastinal surfaces, and Anterior border.
• It is larger than Right Superior Lobe.
• It also has cardiac impression which indents mediastinal surface and produces small thin projection of anterior border called Lingula.

BLOOD SUPPLY AND LYMPHATICS

• Superior Lobe of the Lung gets its blood supply and nutrients via right and left Bronchial Arteries which are usually branches of thoracic Aorta.
• They get Pulmonary blood for oxygenation via Pulmonary arteries from heart. On each side it divides into superior branch which supplies the superior Lobe.
• Lymph from most part drains into Bronchopulmonary Lymph nodes and some of it in Pulmonary Lymph nodes.

FUNCTION

Superior Lobe of the Lung functions mainly to oxygenate the blood via pulmonary circulation as it passes through the alveoli. However it also has non respiratory functions as :

•        Altering the pH of body
•        Conversion of angiotensin I to angiotensin II
•        Filtering of Blood Clots
•        Filtering of gas bubbles in blood
•        Help sound production by providing air
•        Can act as shock absorbent for heart etc.