SANFORD, Fla. -

Medical examiner Valerie Rao testified in the George Zimmerman trial Tuesday. She was not the medical examiner who performed the autopsy on Trayvon Martin.

Rao is a former Miami-Dade County medical examiner who now works in Jacksonville. According to News4Jax.com, she comes with a trail of complaints on her performance.

Before her testimony, prosecutors asked her to review evidence in the case. She said Zimmerman's injuries were "insignificant." And that his head was bumpy.

"They were so minor that the individual who treated and examined Mr. Zimmerman decided stitches weren't required," Rao said.

Rao added that  Zimmerman could have had his head banged on concrete once.

"He didn't have to go to the hospital; he went to a clinic," Rao said. "He was not incapacitated in any way. He walked on his own power."

During cross examination, defense attorney Mark O'Mara showed a projection of pictures showing Zimmerman's injuries.

"We know that there were two injuries that resulted from the impact," Rao said.

Rao's testimony is important, because Zimmerman claims he killed the unarmed 17-year-old, because he feared for his life.