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Apex of left lung

The apex of the left lung is the superior-most portion of the left lung, projecting above the level of the first rib into the root of the neck. It is covered by the cervical pleura (cupula) and lies in close proximity to important neurovascular structures at the thoracic inlet, making it a critical region in thoracic anatomy and imaging.

The lung apex is an important area of assessment on chest radiography, CT, and MRI due to its unique anatomy and relationship to the neck and upper mediastinum.

Synonyms

  • Left lung apex

Location

  • Superior-most part of the left lung

  • Projects approximately 2–3 cm above the medial third of the clavicle

  • Extends into the root of the neck

  • Covered by cervical pleura and suprapleural membrane (Sibson fascia)

  • Situated posterior to the subclavian vein and anterior to the subclavian artery

  • Lateral to the trachea and esophagus

Anatomical components

  • Apical lung parenchyma

  • Visceral pleura

  • Cervical (parietal) pleura

  • Suprapleural membrane (Sibson fascia)

Relations

Anteriorly:

  • Clavicle

  • Subclavian vein

Posteriorly:

  • First rib

  • T1 vertebral body

Medially:

  • Trachea

  • Esophagus

  • Left common carotid artery

Laterally:

  • First rib

  • Scalene muscles

Inferiorly:

  • Upper lobe of the left lung

Structures related to the left lung apex

  • Subclavian artery and vein

  • Brachial plexus (lower trunks)

  • Sympathetic chain and stellate ganglion

  • Thoracic duct (left side)

X-ray appearance

Chest radiograph (PA view):

  • Apical lung field: Radiolucent area above the clavicle

  • Apical pleural cap: Thin soft-tissue density may be seen

  • Clavicle and first rib: Overlie the lung apex

  • Symmetry: Compared with the right apex for assessment

CT appearance

Lung window:

  • Apical parenchyma: Normal aerated lung with low attenuation

  • Pleural surface: Thin, smooth pleural margin

  • Bronchovascular markings: Sparse compared to basal lung regions

  • Thoracic inlet structures: Clearly delineated in relation to lung apex

MRI appearance

T1-weighted images:

  • Aerated lung: Very low signal intensity

  • Pleura: Thin low-signal line

  • Adjacent fat (neck and mediastinum): High signal providing contrast

T2-weighted images:

  • Lung parenchyma: Low signal due to air content

  • Pleura: Low signal

  • Neurovascular structures: Higher signal than lung parenchyma

STIR:

  • Lung apex: Suppressed low signal of aerated lung

  • Soft tissues and pleura: High signal if fluid-containing structures present

CT image

Apex of left lung CT anatomy image -img-00000-00000

X-Ray image

Apex of left lung X RAY anatomy image -img-00000-00000