A rare case is reported of a young woman who suffered from suprascapular nerve entrapment syndrome (SNES) of the right side and two years later developed the same syndrome on the left. At the first operation an anomalous bifid transverse ligament was found and cut. The combination of pressure effect from the congenital defect together with frequent protraction of the shoulder due to her work as a physical education teacher caused triggering of the SNES. The clinical course, electromyographic findings, and differential diagnosis are reported. Cutting of the anomalous ligament on both sides brought relief from pain, weakness, and atrophy of the shoulder muscles, enabling the patient to return to work.