Radial tunnel syndrome is an entity that refers to entrapment of the radial nerve in the forearm, as it occurs in the supinator syndrome. Some authors believe this is an early form of the posterior interosseous nerve syndrome 5.
The syndrome is characterized by pain along the radial aspect of the proximal forearm and, despite it being a compression of a motor nerve, it is characterized by the absence of neurologic deficits. Pain on resisted supination of the forearm and pain on resisted middle finger extension are common 2. Pain may radiate up to the shoulder and neck and is aggravated by use of the hand1.
Electromyographic findings that might suggest or confirm the diagnosis are typically absent.
It is a result of compression of the posterior interosseous nerve (deep motor branch of the radial nerve) as it passes through the lateral muscular septum 1.
Evidence of muscle denervation (oedema or artophy) along the posterior interosseous nerve distribution is the most common finding on MRI 4. This is typically seen within the supinator muscle, followed by the proximal forearm extensor muscles.
MRI may also identify alternative conditions that may explain the patient's symptoms, such as lateral epicondylitis, or may identify compressive lesions that may be amenable to surgical resection or decompression 2.
Treatment and prognosis
Treatment is usually conservative. Some authors suggest surgical decompression to avoid permanent nerve damage.
- 1. Weiss LD, Weiss JM, Pobre T. Oxford American Handbook of Physical Medicine and Rehabilitation. Oxford Univ Pr. (2010) ISBN:0195367774. Read it at Google Books - Find it at Amazon
- 2. Ferdinand BD, Rosenberg ZS, Schweitzer ME et-al. MR imaging features of radial tunnel syndrome: initial experience. Radiology. 2006;240 (1): 161-8. doi:10.1148/radiol.2401050028 - Pubmed citation
- 3. Chien AJ, Jamadar DA, Jacobson JA et-al. Sonography and MR imaging of posterior interosseous nerve syndrome with surgical correlation. AJR Am J Roentgenol. 2003;181 (1): 219-21. AJR Am J Roentgenol (full text) - Pubmed citation
- 4. Ferdinand BD, Rosenberg ZS, Schweitzer ME et-al. MR imaging features of radial tunnel syndrome: initial experience. Radiology. 2006;240 (1): 161-8. doi:10.1148/radiol.2401050028 - Pubmed citation
- 5. Ritts GD, Wood MB, Linscheid RL. Radial tunnel syndrome. A ten-year surgical experience. Clin. Orthop. Relat. Res. 1987;(219): 201-5. - Pubmed citation