Asbestosis and the serratus anterior muscle

Our plain-English summary of Asbestosis and the serratus anterior muscle, by J.D. Collins, R.K. Brown, P. Batra (Journal of the National Medical Association, 1983).

The study

• Authors: J.D. Collins, R.K. Brown, P. Batra
• Journal: Journal of the National Medical Association
• Published: 1983;75(3):296-300
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

Twenty-seven patients with a history of asbestos exposure were reviewed at the UCLA Medical Center in December 1981. All patients were referred by the United States Department of Labor. The patients were told they had asbestosis on the basis of their history of exposure and chest radiographs taken at a local asbestos screening program and initially interpreted by a "B" reader. None of the 27 patients reviewed were found to have evidence of asbestosis either clinically or radiographically. The false-positive radiographic interpretations were due to the extrathoracic musculature (serratus anterior) mimicking intrathoracic disease. Since the study described here was done, an additional 330 patients have had their radiographs reviewed.

In plain English

This study reviewed chest X-rays of patients with assumed asbestos exposure whom the United States Department of Labor referred to the UCLA Medical Center. All arrived with a diagnosis of asbestosis. That diagnosis was based on their exposure history and on X-rays from a regional screening program read by "B" readers, who in most cases looked at a single frontal chest film. The first 27 patients, reviewed in December 1981, showed no evidence of asbestosis clinically or on X-ray. In the full group of 357 patients (350 men and 7 women), 293 had no disease. A chest-wall muscle, the serratus anterior, was prominent in 243. In 252 patients, all male, an inward-curving lower chest wall made the muscle stand out. Two patients had bilateral pleural thickening of undetermined cause. The authors concluded that "B" reader interpretation of limited X-rays had led to false-positive findings described as consistent with asbestosis, with the serratus anterior muscle mimicking pleural disease. They advocated added views and fluoroscopy.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review of chest radiographs (case series) of referred patients, comparing UCLA films (PA, lateral and both oblique views, with fluoroscopy or CT in some) against outside screening films
• Who was studied: 357 patients referred by the United States Department of Labor to the UCLA Medical Center, all arriving with a diagnosis of asbestosis. The first 27 were reviewed in December 1981 and 330 more afterward. Ages ranged from 25 to 84 years (average 56.5); 350 were men and 7 were women.
• Exposure: Assumed exposure to asbestos. The article does not report fiber types, products, jobs or doses.
• Main results:
  • None of the first 27 patients reviewed had evidence of asbestosis, either clinically or radiographically.
  • Of the 357 patients, 293 had no disease, either radiographically or clinically.
  • Serratus anterior muscle prominence was found in 243 of the 357 patients. The table prints this as 81%.
  • 252 patients (printed as 72 percent) had a biconcave lateral lower-third chest wall that accentuated the serratus muscle. None of the seven women showed this concavity. The authors believed this contributed to the false asbestosis readings.
  • Other findings among the 357 were:
• 56 with previous granulomatous disease
• 2 with bilateral pleural thickening of undetermined cause
• 2 with calcification of the diaphragm
• 2 with primary lung tumors
• 2 with apical bullous disease
• 4 with rib fractures and pleural reaction at the fracture sites
  • Five patients had CT scans of the chest. The authors reported that the results confirmed the serratus muscle was mimicking pleural disease.
  • In most cases the "B" reader had reviewed only a single PA chest radiograph.
• The authors' conclusion: The authors concluded that "B" reader interpretation of limited radiographs led to false-positive findings described as consistent with asbestosis. They believed the serratus anterior muscle was the structure that contributed to the diagnosis of pleural disease. They advocated oblique radiographs and fluoroscopy, with CT as a further option in medicolegal cases.
• Limitations the authors state:
  • The "B" readers' original interpretations did not come with the radiographs and were not available to the authors for review.
  • Many outside oblique radiographs were suboptimal because of inadequate rotation.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Chest X-Ray, Intrathoracic.

Related studies

• The serratus anterior muscle on chest radiographs — D. Gilmartin (1979)
• A comparative evaluation of intrathoracic latissimus dorsi and serratus anterior muscle transposition — M.K. Widmer, T. Krueger, et al. (2000)
• The detection of thoracic abnormalities using posterior-anterior (PA) vs PA and oblique roentgenograms — R.B. Reger, R.G. Ames, et al. (1982)
• Asbestos-related pleural disease and asbestosis: a comparison of CT and chest radiography — A.C. Friedman, S.B. Fiel, et al. (1988)
• Effect of tobacco smoking on the presence of asbestosis at postmortem and on the reading of irregular opacities on roentgenograms in asbestos-exposed workers — E. Hnizdo, G.K. Sluis-Cremer (1988)
• Screening of miners and millers at decreasing levels of asbestos exposure: comparison of chest radiography and thin-section computed tomography — M. Terra-Filho, E. Bagatin, et al. (2015)

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