This rare condition results from paralysis of the supraspinatus and infraspinatus muscles caused by damage to the sixth and seventh cervical nerves. Acute trauma to the prescapular area (eg, struggling into a head gate) produces a nonspecific ataxia immediately after the injury. Several days after the injury, the muscles may show signs of wasting, indicating the possibility of permanent damage.
Chronic injury to the nerves causes marked wasting of the muscles within weeks. A specific gait aberration develops. The stride is shorter than normal; when weight is borne on the limb, it tends to swivel. In some cases, the cause may be nerve compression in or around the vertebrae (eg, an abscess or fracture), which may be identified on radiographs.
If the trauma is complicated, primary treatment must be directed toward resolving the immediate problem. However, if the clinical presentation suggests that the injury is localized to the nerve, immediate treatment with steroids or other anti-inflammatory agents is appropriate.
Last full review/revision September 2015 by Paul R. Greenough, FRCVS