Ring finger lumbrical origin strain: a case series with imaging findings.

Lumbrical strain is a relatively unknown hand injury. We report four cases of lumbrical origin strain involving the ring finger flexor tendons. Three patients sustained the injury during rock climbing and one while working with a jackhammer. In all cases, circumferential fluid around the flexor tendons of the ring finger was demonstrated on MRI and/or ultrasound at the distal palmar level at the "bare area," which is normally devoid of a synovial sheath. There is a paucity of information in the literature regarding this injury and its specific imaging features. Lack of awareness of this injury renders accurate diagnosis difficult.