Dysfunction of the Diaphragm

Imaging as a Diagnostic Tool

Nadir Kharma

Disclosures

Curr Opin Pulm Med. 2013;19(4):394-398. 

In This Article

Abstract and Introduction

Abstract

Purpose of review This review summarizes the utility and efficacy of different imaging modalities in the diagnosis of diaphragmatic dysfunction.

Recent findings Dynamic MRI of the diaphragm has been recently described in the literature as a tool allowing more detailed study of diaphragmatic dysfunction.

Summary The diaphragm is the primary muscle of ventilation. Diaphragmatic dysfunction can be partial or complete, unilateral or bilateral. The diagnosis is difficult to establish at certain times due to diversity of presentations and severity of symptoms. There are several causes of diaphragmatic dysfunction, which adds to the complexity of diagnostic workup. In this review, the basic anatomy and function of the diaphragm and the different pathologic processes that may affect its function will be presented. These processes may originate in the brain, spinal cord, phrenic nerve or the diaphragm itself. Furthermore, this article will review the utility and efficacy of different diagnostic modalities in the diagnosis of diaphragmatic dysfunction. Most of these imaging tools have been well known for several years, including plain chest radiographs, fluoroscopy and ultrasound. An emerging mode is magnetic resonance dynamic imaging, which is another potentially effective way of functional diaphragmatic imaging that is still not part of routine clinical practice.

Introduction

The diaphragm has several attachments to the body wall. It has anterior, lateral and posterior attachments. Anterior and lateral attachments include the inferior part of the sternum, xiphoid process, lower six ribs and costal cartilage.[1]

The two diaphragmatic crura attach the diaphragm posteriorly to the upper lumbar vertebral bodies and disks. Both crura are joined by a fibrous median arcuate ligament.[2] The paired medial and lateral arcuate ligaments serve as additional posterior attachments.[3] The medial arcuate ligaments extend over the anterior psoas muscles as fibrous attachments between the transverse processes of L1 and L1 or L2 vertebral body. The lateral arcuate ligaments cover the quadratus lumborum muscle. They extend from the transverse processes of T12 laterally to the middle area of the 12th ribs.

The right and left phrenic nerves innervate the diaphragm. Phrenic nerves originate from cervical nerves C3–C5 and are responsible for diaphragmatic sensory and motor function. The paired phrenic nerves are located in the lateral compartment of the neck posteriorly and travel anteriorly as they course through the thorax. The phrenic nerves travel along the anterior pericardial surface before they reach the diaphragm and start branching over both inferior and superior surfaces of diaphragm.[4]

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