Bioparameter determining device with space-saving component for appendage

A portable device configured to non-invasively determine a tissue bioparameter of a mammalian subject, comprising:

• a light source providing light within the device;
• a digital sensor;
• a processing unit;
• a space-saving component comprising:
• (a) a wall surface including a grooved recess and at least one shoulder;
• and
• (b) a substantially flat cover,
• the cover configured to cover the wall surface by moving from an open position far enough away from the wall surface to allow insertion of an appendage of the subject into a chamber defined by the grooved recess and the cover, to a closed position, the cover comprising a flexible material that, in the closed position, elastically deforms away from the wall surface when the appendage is present in the grooved recess and restores to a substantially flat state when the appendage is absent from the grooved recess, wherein in the closed position, when the appendage is absent from the recess, the cover is adjacent the at least one shoulder,
• the chamber configured to receive the appendage such that the appendage is deployed adjacent the digital sensor and faces the light source.