retracted claw
When a cat walks, its claws retract into a cutaneous fold (sheath) and it moves on its pads.
distal phalanx 
Bone of the lower terminal end of the toe bearing the claw.
proximal phalanx 
Bone of the upper terminal end of the toe connected to the metacarpus.
tendon 
Fibrous tissue connecting the muscle to the bone; relaxing the tendon causes the claw to retract.
middle phalanx 
Bone of the central part of the toe between the proximal and distal phalanges.
claw 
Curved pointy retractable corneous structure allowing the cat to climb, catch its prey and defend itself.