Dew claw
From Wookieepedia, the Star Wars wiki.
The dew claw was a retractable, curved claw enclosed the underside of the Yevethan wrist. These claws could extend to almost a foot in length for use in close combat and dominance killing.
[edit] Behind the scenes
Alien Anthology contradicts all other descriptions and images of dew claws, displaying them as a pair of blades protruding from either side of the wrist, as opposed to a single blade from below the wrist. See this image for reference.
Yevethan dew claws are likely named after the vestigal dewclaw of some Earth creatures.
