Pronator teres syndrom (abbreviated to pronator syndrome) affects a part of the median nerve in the forearm. Localised swelling could cause compression of this nerve against the edge of a forearm muscle (pronator teres muscle). Occasionally, there are thick fibrous bands which could be responsible for the pinching of the nerve. However, symptoms can also result from carrying out certain repetitive activities leading to an excessive enlargement (hypertrophy) of the above mentioned muscle.
X-rays should always be taken of the elbow in order to rule out the cause as bony projections (supracondular process of the humerus) on the bone of the upper-arm. Clinical evidence is the presence of pain and tingling in the area of the middle finger and in the palm. Later there is a weakness in the thumb and in the flexing of the radial side fingers. Signs of advanced pronator syndrome are muscle atrophy in the balls of the thumb as well as compression pain in the forearm along the nerve path.
Should conservative therapy through immobilisation, localised ultrasound or cortisone injections fail, an operative intervention should follow. As part of operative aftercare, it is necessary to wear an upper-arm cast for approximately 10 days.
Pronator syndrome is a nerve compression syndrome.
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