Discrimination between axonotmesis and neurotmesis is crucial in traumatic nerve injury. We present the case of a 43-year-old woman which presented hypoesthesia in the fourth and fifth right fingers, started after surgery for Dupuytren syndrome. At ultrasound study, the ulnar digital sensory branch was identified. Before the division into the two terminal branches, a neuroma was observed, while neurotmesis was excluded. This case shows the utility of ultrasonography in peripheral nervous system examination and the possibility of visualization of very small nerves and their terminal branches.