case_images: PMC6350128_01
case_images: Intra-operative findings. Hematoma formed in the mesoneurium (perineural
  membrane) noted after incising through Osborne's ligament.
case_images: 10.1177_2050313X18824814-fig1.jpg
case_images: PMC6350128_01_10.1177_2050313X18824814-fig1.jpg
case_images: fig1-2050313X18824814
case_images: On exploration of the cubital tunnel, the ulnar nerve was noted to be compressed underneath the Osborne's ligament due to a hematoma that had formed in the mesoneurium (perineural membrane) presumably originating from the medial triceps muscle (Figure 1).