Proximal Median Nerve Compression
PROXIMAL MEDIAN NERVE COMPRESSION
Repetitive tasks involving: throwing, gripping, pronation (turning your hand to a palm down position), and sudden extension at the elbow can produce injury resulting in compression of the median nerve at the elbow and forearm level. Weight lifting may result in building muscle mass and can lead to nerve compression. Trauma to the upper forearm may also result in scarring and can induce compressive neuropathies at and around the elbow. Your own inherent anatomy may be a variant that makes you vulnerable to this condition. Further, it is common to be predisposed to this nerve compression if you are diabetic. Diagnosing this condition is very dependent upon the clinical evaluation and is often missed by electro-diagnostic studies ( nerve conduction, EMG).
In pronator syndrome, night pain is less common (but does occur) while carpal tunnel syndrome often wakes patients with complaints of aching and numbness in the hands.
The physical examination may reveal tenderness and a Tinel sign over the pronator teres muscle. Weakness, if present, may involve the index finger, thumb flexion and pinch strength. Atrophy in the thenar muscles (base of thumb in palm) may be noted in advanced cases.
Loss or decreased sensibility of the thumb and index/long fingers are consistent with both proximal median nerve compression and carpal tunnel syndrome. Loss of sensation and/or pain in the palmar area on the thumb sites is suggestive of pronator syndrome. Provocative (exertional) tests on exam can be helpful in eliciting signs of pronator syndrome.
Anterior Interosseus Nerve Syndrome (AIN Syndrome)
Anterior interosseus nerve syndrome again is more rare, but usually resolves with time, particularly if it is secondary to minor trauma or irritation to the nerve. However proximal median compression in the diabetic limb usually, ultimately requires surgery and is generally found coexisting with other compressions in the same extremity.
If no improvement with time and therapy are noted or if a space occupying lesion/mass is identified on the MRI, surgical release is then recommended.