onography has been shown to be an excellent method to assess peripheral nerves, showing high accuracy in the diagnosis of many nerve disorders. With sonography, the peripheral nerves of an entire extremity can be visualized in high resolution in less time than is required with magnetic resonance imaging. With real-time examination of a peripheral nerve, direct feedback can be obtained from the patient, as transducer pressure over an abnormal nerve or neuroma commonly elicits symptoms, which serves to increase diagnostic accuracy. Evaluation of peripheral nerves dynamically either during joint movement or muscle contraction is easily completed using sonography. 1 The purpose of this article is to review the normal sonographic appearance of peripheral nerves and to review common nerve disorders, including nerve entrapment, intraneural ganglion cyst, nerve trauma, and peripheral nerve sheath tumors.
Sonography of Normal Peripheral NervesThe characteristic appearance of peripheral nerves on sonography is best appreciated in the short axis relative to the nerve, where the individual nerve fascicles will appear hypoechoic, surrounded by hyperechoic connective tissue (Figure 1). 2 This appearance is likened to a honeycomb. The more proximal nerve trunks are surrounded by hyperechoic fat, and each nerve trunk can be followed distally until only one nerve fascicle remains. In the long axis relative to the nerve, the fascicular appearance can also be appreciated, with
REVIEW ARTICLESonography is now considered an effective method to evaluate peripheral nerves. Low cost, high resolution, the ability to image an entire limb in a short time, and dynamic assessment are several of the positive attributes of sonography. This article will review the normal appearance of peripheral nerves as shown with sonography. In addition, the most common applications for sonography of the peripheral nerves will be reviewed, which include entrapment neuropathies, intraneural ganglion cyst, nerve trauma, and peripheral nerve sheath tumors. Clinical information related to nerve disorders is also included, as it provides valuable information that can be obtained during sonographic examinations, increasing diagnostic accuracy.