Teaching Video NeuroImages: Hourglass-like fascicular constriction in Parsonage-Turner syndrome

A 43-year-old woman presented with intense pain in the left upper arm, a plegic flexor pollicis longus, and flexor digitorum profundus of the 2nd digit without sensory symptoms occurring 8 days after a hysterectomy. Needle myography showed acute denervation and absent volitional motor activity of affected muscles. The patient was diagnosed with Parsonage-Turner syndrome (PTS) (figures 1 and 2, video 1).