The Elbow

Arch Orthop Trauma Surg 1979 Apr 30;93(4):307-12

Syndromes of compression of the median nerve in the proximal forearm (pronator teres syndrome; anterior interosseous nerve syndrome).

Nigst H, Dick W

Entrapment of the median nerve in the proximal forearm is seen in two forms: the pronator teres syndrome, and the anterior interosseous nerve (or Kiloh-Nevin) syndrome. Both syndromes are rare, and they comprised approximately 1% of the compression syndromes of the upper limb which were treated operatively by the authors. The symptoms, signs, etiologies, and intraoperative findings are discussed. It is pointed out that certain of the clinical features may resemble those of irritation of the median nerve by a supracondylar process or Struthers' ligament. although both proximal median entrapment syndromes have a favorable prognosis when treated non-operatively, the authors recommend operative treatment in cases in which there is no perceptible improvement following 8 weeks of non-operative treatment, since this is likely to speed and enhance recovery. Nine cases of the pronator teres syndrome (8 treated successfully by operation, 1 failure) and 2 cases of the anterior interosseous nerve syndrome (both fully recovered) are added to the cases reported previously in the literature.

J Hand Surg [Br] 1994 Dec;19(6):709-10

Median nerve compression within the humeral head of pronator teres.

Tulwa N, Limb D, Brown RF

St James's University Hospital, Leeds, UK.

We describe a case of the pronator syndrome caused by compression of the median nerve by a fibrous band as the nerve passed through the humeral head of origin of pronator teres. This rare anatomical arrangement resulted in displacement of the median nerve to the anterior aspect of the medial humeral epicondyle and, as far as we are aware, has not previously been described as a site of compression neuropathy.

Surg Radiol Anat 1990;12(4):267-71

Median nerve entrapment. Pronator teres syndrome. Surgical anatomy and correlation with symptom patterns.

Fuss FK, Wurzl GH

First Department of Anatomy, University of Vienna, Austria.

The surgical anatomy of interest in the pronator teres syndrome was studied to shed light on the ramifying pattern of the median nerve, the number of its muscular branches and their branching levels and to pinpoint the location of the fibrous bands which may cause median nerve entrapment. The fibrous arch of the pronator teres muscle (pronator arch) was found to lie 3 cm to 7.5 cm below Hueter's line, that of the flexor digitorum superficialis muscle (superficialis arch), which is distal to the pronator arch, was found to lie 6.5 cm below Hueter's line in its most proximal position. Symptom patterns in terms of muscle weakness caused by median nerve entrapment at different levels were also evaluated.

J Bone Joint Surg [Am] 1981 Jul;63(6):885-90

The pronator teres syndrome: compressive neuropathy of the median nerve.

Hartz CR, Linscheid RL, Gramse RR, Daube JR

Thirty-nine patients with a clinical diagnosis of the pronator teres syndrome were seen during a seven-year period. They typically complained of aching discomfort in the forearm, weakness in the hand, and numbness in the thumb and index finger. Cyclic stress usually brought on the symptoms. The distinctive physical finding was tenderness over the proximal part of the pronator teres, which was aggravated by resisted pronation of the forearm, flexion of the elbow, and occasionally by resisted contraction of the flexor superficialis of the long finger. Electrophysiological testing of the median nerve showed abnormalities in a few patients, but localization of the abnormality was possible only rarely. Intraoperative recordings showed some improvement shortly after release of the median nerve in six of the ten forearms that were tested. Surgical exploration of thirty-six forearms in thirty-two patients showed intramuscular tendinous bands in the pronator, indentation of the muscle belly of the flexor superficialis in most forearms. Vascular and muscular abnormalities were seen occasionally. Of the thirty-six operations, twenty-eight gave good or excellent results; five, fair; and in three patients the symptoms were unchanged. The cause of failure was either inadequate decompression or misdiagnosis.

Bull Hosp Joint Dis 1976 Apr;37(1):59-62

Pain and the pronator teres syndrome.

Farrell HF

Extremely painful paresthesias and mild motor weakness of the hand were relieved by sectioning the deep head of the pronator teres muscle and the fibrous arch of the flexor digitorum superficialis, thereby freeing the median nerve and its anterior interosseous branch. The characteristic pinch deformity of the thumb and index fingers usually described in anterior interosseous-nerve syndrome was not present. A Tinel sign at the level of the pronator teres was present.

J Neurol Neurosurg Psychiatry 1976 May;39(5):461-4

Pronator syndrome: clinical and electrophysiological features in seven cases.

Morris HH, Peters BH

The clinical and electrophysiological picture of seven patients with the pronator syndrome is contrasted with other causes of median nerve neuropathy. In general, these patients have tenderness over the pronator teres and weakness of flexor pollicis longus as well as abductor pollicis brevis. Conduction velocity of the median nerve in the proximal forearm is usually slow but the distal latency and sensory nerve action potential at the wrist are normal. Injection of corticosteroids into the pronator teres has produced relief of symptoms in a majority of patients.

Hand Clin 1992 May;8(2):307-15

Proximal median nerve compression.

Eversmann WW

Iowa Medical Clinic, Cedar Rapids.

Compression neuropathies of the median nerve in the proximal forearm are unusual lesions. Many patients have vague symptoms for many months or even years prior to confirming the diagnosis of either pronator syndrome or anterior interosseous syndrome of the forearm. Serial examinations clinically and electrodiagnostically may be necessary at intervals of 6 to 8 weeks as required for the evaluation of the patient's symptoms. As with other compression neuropathies, the diagnosis is solely dependent on the diagnosis of neuropathy of the median nerve using whatever parameter satisfies the surgeon's diagnostic criteria and then having made that diagnosis, localizing the site of that neuropathy by physical examination or electrodiagnosis with the support of radiographic techniques as appropriate. Surgical exploration of proximal median nerve compression is normally followed by prompt and predictable recovery from the median neuropathy and clinical symptoms between 8 and 12 weeks after surgical exploration. Prolonged symptom complexes after surgical exploration of the proximal median nerve are, in my experience, due to either (1) extremely severe median nerve injury secondary to pronator syndrome with prolonged recovery and distal nerve axomnetic recovery into the hand, or (2) sensory nerve dysesthesis of the small sensory nerves on the proximal volar surface of the forearm. The symptoms of either of these postoperative findings normally improve with time.

J Neurosurg Sci 1987 Jan-Mar;31(1):1-5

The pronator teres syndrome. Clinical and electrophysiological features in six surgically verified cases.

Gessini L, Jandolo B, Pietrangeli A

Six surgically verified cases of pronator teres syndrome are reported. The anatomy of the median nerve at the upper third of the forearm, the relationships between the nerve and the pronator teres muscle and the serial innervation of the muscles of the forearm supplied by the n. medians are described. Clinical and electrophysiological features are reported in detail and their contribution in diagnosing the lesion is discussed.

Acta Neurochir (Wien) 1988;91(3-4):144-6

Anterior interosseous nerve syndrome with atypical nerve course in relation to the pronator teres.

Megele R

Neurochirurgische Abteilung, Krankenhaus der Barmherzigen Bruder, Regensburg, Federal Republic of Germany.

A case of anterior interosseous nerve palsy is demonstrated due to an anatomical variation not recorded before causing this syndrome. Main median-nerve trunk and anterior interosseous nerve passed differently in relation to the pronator teres muscle. Surgery led to a rapid recovery of nerve function.

Orthop Rev 1990 Oct;19(10):888-92

The pronator compression test revisited. A forgotten physical sign.

Gainor BJ

Department of Surgery, University of Missouri School of Medicine, Columbia.

Pronator compression testing is a valuable clinical feature of median nerve entrapment diagnosis. Of 10 patients with this disorder, all developed paresthesias preoperatively in the hand after 30 seconds or less of manual compression of the median nerve at or near the pronator muscle. Eight patients had a positive Tinel's sign at the impingement site, but only one patient had a positive electromyographic result. More than 50% of the patients had undergone previous carpal tunnel release or were diagnosed at presentation with double crush syndrome. All patients had a good or excellent result from surgical decompression of the median nerve in the forearm, except for one workers' compensation case who had excellent postoperative strength testing but multiple residual complaints. Pronator compression testing is a helpful and dependable physical sign in the diagnosis of pronator syndrome.

J Neurol Neurosurg Psychiatry 1983 Nov;46(11):1047-9

Median nerve compression by Struthers ligament.

Suranyi L

A 61-year-old patient presented with progressive weakness, pain and numbness in the left arm and hand. On examination the abnormalities were confined to the distribution of the median nerve, and electrophysiological testing localised the lesion to the segment just proximal to the elbow. At surgery Struthers ligament was found compressing the median nerve. No bony spur was found by palpation or on radiological examination.

Neurosurgery 1990 Nov;27(5):787-9

Entrapment neuropathy of the median nerve at the level of the ligament of Struthers.

Bilge T, Yalaman O, Bilge S, Cokneseli B, Barut S

Department of Neurosurgery, Taksim Hospital, Istanbul, Turkey.

The presence of a supracondylar process and Struthers' ligament is a rare congenital anomaly that may cause compression of either the median nerve, the brachial artery, or both. The authors present a case in which the supracondylar process and Struthers' ligament compressed both the median nerve and the brachial artery. This case is unusual, in that the symptoms of compression of the brachial artery increased--namely, the pulse intensity decreased and the pain increased with elbow flexion.

Am J Phys Med Rehabil 1991 Oct;70(5):274-7

The pronator syndrome. An evaluation of dynamic maneuvers for improving electrodiagnostic sensitivity.

Mysiew WJ, Colachis SC 3d

Department of Physical Medicine, Ohio State University, Columbus 43210-1290.

The role of three test maneuvers (elbow flexion, forearm pronation and finger flexion against resistance) in improving sensitivity of conventional nerve conduction studies used in cases of suspected pronator teres syndrome were evaluated in 11 healthy control subjects and 10 patients with the clinical diagnosis of pronator teres syndrome. Stimulation of the median nerve was performed above and below the elbow before exercise and immediately after the test maneuvers; the resultant median motor and sensory responses were recorded. Before and after exercise, median motor and sensory responses (e.g., amplitude, latency, velocity) did not differ significantly between the two groups; only one patient with suspected pronator teres syndrome developed sensory amplitude changes after exercise. We concluded that these test maneuvers did not significantly improve the sensitivity of conventional nerve conduction studies in the diagnosis of pronator teres syndrome.

J Hand Surg [Am] 1994 Jan;19(1):121-6

Median nerve compression in the proximal forearm.

Olehnik WK, Manske PR, Szerzinski J

Division of Orthopedic Surgery, Washington University School of Medicine, St. Louis, MO 63110.

Thirty-nine limbs in 36 patients underwent surgical decompression of the median nerve in the proximal forearm. Seventeen patients with 19 limbs had prior ipsilateral carpal tunnel releases, and 24 had workers' compensation claims related to heavy labor or repetitive tasks. The most common presenting complaints were paresthesias/numbness in the distribution of the median nerve and pain in the forearm or hand. The most common physical finding was a positive pronator compression test, followed by median nerve hypesthesia. Elbow to wrist nerve conduction tests were obtained in 37 of 39 limbs and were abnormal in 12. Intraoperatively, the nerve was compressed at the flexor digitorum superficialis tendon in 22 limbs, pronator teres in 13 limbs, and both in 4 limbs. Postoperatively, 30 limbs had complete or partial relief of symptoms; in a sub-group of 19 limbs that had a prior failed carpal tunnel release, 14 had complete or partial relief. although there was a trend toward better results in patients with normal preoperative nerve conduction tests and intraoperative compression at the flexor digitorum superficialis, the difference was not significant.