C7 radiculopathy: importance of scapular winging in clinical diagnosis.
Makin GJ., Brown WF., Ebers GC.
Lesions of the seventh cervical (C7) root are common and cause a readily recognised neurological syndrome. Recognition of this pattern is essential in differentiating C7 root lesions from lesions of the brachial plexus or peripheral nerves. Serratus anterior weakness is not generally included in this syndrome. We report six verified cases of C7 radiculopathy in which weakness of the serratus anterior was present in addition to the usual findings. This was manifest as winging of the scapula, when pushing forward against a wall, either with the hands at shoulder level or, in some cases, only when the hands were lowered to waist level. This latter method of testing places the muscle at a mechanical disadvantage and reveals partial paralysis. Analysis of this clinical finding complements anatomical evidence suggesting that the powerful lower digitations of the muscle may be primarily supplied by the C7 root in some cases. Scapular winging, apparent either in the usual position or the modified position described here, should be recognised as consistent with a diagnosis of C7 radiculopathy. When present, this sign serves to differentiate C7 radiculopathy from lesions of the brachial plexus or radial nerve.