Posterior junction line
Linea junctionis posterior
Definition
The posterior junction line results from the apposition of the lungs posterior to the esophagus
and anterior to the 3rd to 5th thoracic vertebrae. Similarly to anterior junction line, it is formed by four layers of pleura.
Normal radiographic appearance:
Posterior junction line appears as a thin straight line projecting through the trachea. Unlike anterior junction line, it can be seen above the clavicles.
The posterior junction line has reportedly been seen on 32% of posteroanterior chest radiographs.
Abnormal radiographic appearance:
Abnormal bulging, convexity or obliteration of this line suggests a posterior mediastinal abnormality. Further clues to the location of a mass can be inferred from the lateral margins of the mass above the clavicles.
As with the anterior junction line, volume loss or hyperinflation of the surrounding lung can also displace the line
References
Gibbs JM, Chandrasekhar CA, Ferguson EC, Oldham SA. Lines and stripes: where did they go?--From conventional radiography to CT. Radiographics. 2007 Jan-Feb;27(1):33-48. doi: 10.1148/rg.271065073. PMID: 17234997.
Marano R, Liguori C, Savino G, Merlino B, Natale L, Bonomo L. Cardiac silhouette findings and mediastinal lines and stripes: radiograph and CT scan correlation. Chest. 2011 May;139(5):1186-1196. doi: 10.1378/chest.10-0660. PMID: 21540217.
Cardiac silhouette findings and mediastinal lines and stripes: X-ray and computed tomography correlation R. Marano, G. Savino, C. Liguori, A. Meduri, L. Natale, L. Bonomo; Rome/IT CR-222 poster ECR 2009
Mediastinal lines, stripes and interfaces on PA chest radiograph with CT correlations - N. Bystrická, H. Poláková, J. Sykora; Bratislava/SKC-0442ECR 2013 10.1594/ecr2013/C-04
