Conduction along the articular branch of the suprascapular nerve.

The maximum sensory conduction velocity was measured along the articular branch of the suprascapular nerve. The potential was evoked by stimulating in the perception area of the nerve above the glenohumeral joint and recorded by an electrode near the suprascapular nerve in the supraclavicular fossa. The maximum conduction velocity averaged 42 m/s, SD 4.6 m/s (20 normal subjects); it decreased slightly with age. When correcting for the error in distance arising from the measurement by obstetric calipers (20%), the maximum conduction velocity averaged 50 m/s. The peak-to-peak amplitude of the main component of the sensory potential was 0.8 muV, SD 0.5 muV. In one of seven patients with a pain syndrome in the shoulder secondary to a brachial plexus neuropathy the velocity and the amplitude of the sensory potential was diminished. In five other patients with pain in the region of the shoulder the conduction velocity was normal but the amplitude was diminished.