Radial Tunnel Syndrome at the Elbow
Melinda McMillen: Jordan Utley & Jenn Ostrowski
Section 1 Introduction to the Pathology
Incidence of the Pathology
Radial tunnel syndrome (RTS) is cause by pressure on the radial nerve either by
repetitive motions of the wrist/elbow or by a direct blow to the elbow. Activities that may
increase the risk for developing RTS are:
 Contact sports such as soccer, rugby or football
 Inadequate warm-up before practice or play
 Diabetes mellitus
 Hypothyroidism (underactive thyroid gland)
 Occupations, such as an assembly line, where the hands are used frequently to do
fine movements (Radial Tunnel Syndrome (radial [posterior interosseous] nerve,
2010)).
Etiology
Radial tunnel syndrome can be causes by multiple factors. One of the more
common mechanisms of injury is if the radial tunnel is too small for any reason and then
the puts pressure on the nerve and it can become pinched and cause pain. Constant use of
the arm and repetitive motion of the elbow and wrist such as twisting, gripping, pushing
and pulling can stretch and irritate the nerve even more. Another common form of injury
is from a direct blow to the lateral side of the arm/elbow (Klein).
<Photo 1: Etiology>
Section 2 Anatomy & Physiology of the injury
Anatomy
The radial nerve starts at the lateral side of the neck where the individual nerve
roots from the brachial plexus exit the spine through the neural foramina. The radial
nerve is one of three main nerves that run down the arm to the hand. The nerve travels
down the posterior side of the upper arm and runs along the lateral side of the elbow this
is where the nerve passes into the radial tunnel, formed by muscles and bone. Passing
through the tunnel the radial nerve runs below the supinator muscle. This is where is
splits off into the superficial and deep branches (Radial Tunnel Syndrome, 2006).
<Photo 2: Anatomy>
<Photo 3: nerve pathways>
Physiology
Radial tunnel syndrome can be causes by two different mechanisms: a specific,
acute incident like a direct blow to the elbow or a more chronic onset brought about by
repetitive motions. The radial nerve branches spread to the back of the forearm. RTS
occurs when this nerve is compressed as it passes through the radial tunnel near the
elbow. With repetitive motions the radial nerve can become stretched or irritated from
overuse (Is It Tennis Elbow or Radial Tunnel?, 2011). “With humeral fractures, the
radial nerve is damaged 12 percent of the time (Starkey, Brown, Ryan, 2010).”
Section 3 Evaluation of the injury
Signs and Symptoms
Symptoms of radial tunnel syndrome are located distally on the forearm and may
be reproduced with resisted supination of the hand and resisted extension of the middle
finger (Starkey, Brown, Ryan, 2010). Patient reports of tenderness and pain over the
radial tunnel and weakness in the muscles on the back of the forearm and wrist especially
with gripping activities and pain with twisting motions of the hand (Radial Tunnel
Syndrome (radial [posterior interosseous] nerve). 2010)
Special Tests: Defining Practice Evaluation
Radial tunnel syndrome can be evaluated through Tinnel’s Sign. This special test
is performed by bending the elbow and tapping on the radial nerve between the olecranon
and the lateral epicondyle. A positive sign will reproduce pain and/or results in a burning
sensation in the hand (Starkey, Brown, Ryan, 2010).
<Video 1: Tinnel Sign>
Double Click to play
Palpation tenderness over the wrist extensor is also indicative of RTS (Neal, Sara
L., MD, MA, Fields, Karl B, MD,. 2010).
<Photo 4: extensor muscles palpation>
Section 4 Associated Differential Diagnoses
Radial tunnel syndrome closely resembles lateral epicondylalgia also known as
tennis elbow. Distinguishing between the two can be very difficult because physical
examination maneuvers that aggravate RTS are usually also positive on a patient with
lateral epicondylalgia. The most effective factor to differentiate between the two
pathologies is the point of maximal tenderness. “ In radial tunnel syndrome, this point is
over the anterior radial neck; in tennis elbow, it is at the origin of the extensor carpi
radialis brevis muscle” (Neal, Sara L., MD, MA, Fields, Karl B, MD,. 2010).
<Photo 5: differential diagnosis>
Section 5 Prognosis & Recent Evidence Informing Best Clinical Care
Prognosis
If treated properly, then the symptoms of radial tunnel syndrome typically resolve
and decrease over time. “It is hard to give a specific time period or percentage of
outcomes due to variations in outcome measures, the severities of RTS and the
inconsistencies in duration, type of intervention, and follow up time for interventions.”
Rarely, surgery is necessary to free the compressed nerve (Standard of Care: Radial
Tunnel Syndrome, 2007).
Resent Research
After modifying the activity of a patient presenting with RTS another form of
management being recently utilized is injections. Typically used to relieve pain is a local
anesthetic and a corticosteroid. “In 1 study of 25 patients with RTS, 18 patients (72%)
had resolution of their symptoms with a single injection of 2 mL 1% lidocaine and 40 mg
of triamcinolone in 1 mL of carrier at 6 weeks of follow-up and 16 patients continued to
have long-term pain relief at greater than 2 years”.
A point of controversy in management of RTS relief is the use of surgery to
decompress the radial nerve; opinions differ from surgeon to surgeon. Although there are
any reports and individual case studies supporting the efficacy of surgical intervention
there has been no randomized controlled trial that compares surgical with non-surgical
treatment or with a placebo.
For more information of these above topics see article below.
Dang, A.C., MD, Rodner, C.M., MD. (2009). Unusual Compression Neuropathies of the
Forearm, Part I: Radial Nerve. Retrieved June 1, 2013, from
http://musculoskeletalinstituteofnewengland.org/clinical_services/orthopaedic/han
dwrist/pdfs/article_radialnerve.pdf
REFERENCES
Dang, A.C., MD, Rodner, C.M., MD. (2009). Unusual Compression Neuropathies of the
Forearm, Part I: Radial Nerve. Retrieved June 1, 2013, from
http://musculoskeletalinstituteofnewengland.org/clinical_services/orthopaedic/han
dwrist/pdfs/article_radialnerve.pdf
Is It Tennis Elbow or Radial Tunnel?. (2011). APEX Network Physical Therapy.
Retrieved May 31, 2013, from
http://www.apexnetworkpt.com/2011/08/it-tennis-elbow-or-radial-tunnel
Klein, David M, MD. Kennedy-White Orthopaedic Center. Retrieved May 31, 2013
from,
http://www.kwoc.net/radial%20tunnel%20syndrome.pdf
Neal, Sara L., MD, MA, Fields, Karl B, MD,. (2010). Peripheral Nerve Entrapment and
Injury in the Upper Extremity. American Family Physician 15;81(2):147-155.
Retrieved from
http://www.aafp.org/afp/2010/0115/p147.html
Radial tunnel Syndrome. (2006). Orthogate. Retrieved June 1, 2013 from,
http://www.orthogate.org/patient-education/elbow/radial-tunnel-syndrome.html
Radial Tunnel Syndrome (radial [posterior interosseous] nerve). 2010. Washington
Orthopeadics and Sports Medicine. Retrieved June 1, 2013 from,
http://www.wosm.com/index.php/component/content/article/121-radial-tunnelsyndrome-radial-posterior-interosseous-nerve
Standard of Care: Radial Tunnel Syndrome. (2007). The Brigham and Women’s
Hospital, Department of Rehabilitation Services. Retrieved June 1, 2013, from
http://www.brighamandwomens.org/Patients_Visitors/pcs/rehabilitationservices/P
hysical%20Therapy%20Standards%20of%20Care%20and%20Protocols/ElbowRadial%20Tunnel%20Syndrome.pdf
Starkey, C., Brown, S., Ryan, J. (2010). Examination of Orthopedic and Athletic Injuries
(3rd ed.). Philidelphia, PA: F.A. Davis Company.