II. Definitions
- Pronator Syndrome
- Forearm compression of the Median Nerve between the two heads of the pronator teres Muscle
- Slow, insidious onset over the course of months to years with pronator overuse (hammering, backhand tennis swing)
- Anterior Interosseous Nerve Entrapment
- Affects Motor Nerve for deep ForearmMuscles (flexor pollicis longus, flexor digitorum profundus)
- Nerve injury results in weakness in making the "OK" sign
III. Differential Diagnosis
IV. Symptoms
- Forearm volar discomfort and ache
- Provoked with elbow extension
- Paresthesias in the thumb, index and middle finger
V. Signs
- Sensory loss over thenar eminence (not present in Carpal Tunnel Syndrome)
- Tinel Sign absent (contrast with Carpal Tunnel Syndrome)
- Phalen maneuver (contrast with Carpal Tunnel Syndrome)
- Normal forearm Sensation
- Sensation in fingers may also be normal
- Pronator Syndrome
- Pronation against resistance from neutral elbow position to elbow extension
- Positive test if pain and Paresthesias occur with maneuver
- Anterior Interosseous Nerve Entrapment
- Weakness in maintaining the "OK" sign against resistance
VI. Management
- Modify activity avoiding provocative measures
- Consider steroid injection (Pronator Syndrome)
- Consider brief Splinting with elbow at 90 degrees (risk of loss of elbow range of motion)
- Surgery indications
- Space occupying lesion
- No improvement with 3-4 months of conservative therapy
VII. Course
- Anticipate 3-6 month course with therapy