This clearly is a human arm. We can look at this type of glyph in my clyph catalogue.

The direction of the thumb is towards the right, i.e. it is a left arm. At least if we consider it from our own viewpoint = the viewpoint of the writer.

In Keiti we have these glyphs of this general type:

Ea4-19 Ea8-108 Eb1-35 Eb2-12 Eb3-14 Eb3-16

Eb2-12 does not look marked in any way, a perfectly normal arm. What may it mean? Is it a sign for giving? No, I would rather guess it is a sign for receiving.